Pub Date : 2024-07-22DOI: 10.1016/j.orgel.2024.107100
Perovskite solar cells (PSCs) are emerging as leading contenders in next-generation photovoltaic technology due to their high theoretical power conversion efficiency (PCE) limits and reduced fabrication costs. Organic framework materials, celebrated for their vast specific surface areas, abundant binding sites, tunable nanostructures, and synergistic effects, are extensively utilized to assist in the fabrication of PSCs. These materials are primarily employed to enhance the photovoltaic performance of PSCs. This review systematically explores the synthesis and functionalization of organic framework materials and their application across various layers of PSCs. Additionally, this review delves into how early-stage MOF synthesis routes and functionalization techniques impact the modification outcomes of later-stage MOF-modified PSCs. Finally, this review offers conclusions and prospects for organic framework materials in PSCs.
{"title":"A comprehensive review of organic frameworks: From synthesis to perovskite solar cells fabrication","authors":"","doi":"10.1016/j.orgel.2024.107100","DOIUrl":"10.1016/j.orgel.2024.107100","url":null,"abstract":"<div><p>Perovskite solar cells (PSCs) are emerging as leading contenders in next-generation photovoltaic technology due to their high theoretical power conversion efficiency (PCE) limits and reduced fabrication costs. Organic framework materials, celebrated for their vast specific surface areas, abundant binding sites, tunable nanostructures, and synergistic effects, are extensively utilized to assist in the fabrication of PSCs. These materials are primarily employed to enhance the photovoltaic performance of PSCs. This review systematically explores the synthesis and functionalization of organic framework materials and their application across various layers of PSCs. Additionally, this review delves into how early-stage MOF synthesis routes and functionalization techniques impact the modification outcomes of later-stage MOF-modified PSCs. Finally, this review offers conclusions and prospects for organic framework materials in PSCs.</p></div>","PeriodicalId":399,"journal":{"name":"Organic Electronics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141773233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-17DOI: 10.1016/j.orgel.2024.107097
The interest in all-inorganic perovskite solar cells (PSCs) featuring a p-i-n structure is on the rise, attributed to their superior heat resistance and adaptability with tandem cell methods. However, their progress has been far from the regular structure owing to the comparatively low open circuit voltage (Voc). This research employs phenylethylammonium iodide, incorporating various side groups, as passivators to tackle the previously mentioned problems and investigate their effects on passivation. It is found that a reduction of trap-state density in perovskite film was accomplished due to the PEAI effective passivation effect by establishing coordination with the under-coordinated Pb2+ ions. Furthermore, there was an enhancement in the alignment of energy levels at the CsPbI2Br perovskite/PCBM junction, resulting in better charge extraction from the CsPbI2Br layer to the charge transport layer. As a result, an improved champion efficiency of 14.26 % with a Voc of 1.11 V, Jsc of 16.21 mA/cm2, and FF of 79.28 % was yielded for the PEAI treatment inverted CsPbI2Br device, compared with the 12.15 % efficiency of the control device. Superior device stability was exhibited for the optimal PEAI-treated devices without encapsulation. This research validates the significance of a side group on a surface passivation molecule to effectively passivate defects and optimize energy levels, especially for boosting Voc.
{"title":"Effective surface treatment for efficient and stable inverted inorganic CsPbI2Br perovskite solar cells","authors":"","doi":"10.1016/j.orgel.2024.107097","DOIUrl":"10.1016/j.orgel.2024.107097","url":null,"abstract":"<div><p>The interest in all-inorganic perovskite solar cells (PSCs) featuring a p-i-n structure is on the rise, attributed to their superior heat resistance and adaptability with tandem cell methods. However, their progress has been far from the regular structure owing to the comparatively low open circuit voltage (<em>V</em><sub>oc</sub>). This research employs phenylethylammonium iodide, incorporating various side groups, as passivators to tackle the previously mentioned problems and investigate their effects on passivation. It is found that a reduction of trap-state density in perovskite film was accomplished due to the PEAI effective passivation effect by establishing coordination with the under-coordinated Pb<sup>2+</sup> ions. Furthermore, there was an enhancement in the alignment of energy levels at the CsPbI<sub>2</sub>Br perovskite/PCBM junction, resulting in better charge extraction from the CsPbI<sub>2</sub>Br layer to the charge transport layer. As a result, an improved champion efficiency of 14.26 % with a <em>V</em><sub>oc</sub> of 1.11 V, <em>J</em><sub>sc</sub> of 16.21 mA/cm<sup>2</sup>, and FF of 79.28 % was yielded for the PEAI treatment inverted CsPbI<sub>2</sub>Br device, compared with the 12.15 % efficiency of the control device. Superior device stability was exhibited for the optimal PEAI-treated devices without encapsulation. This research validates the significance of a side group on a surface passivation molecule to effectively passivate defects and optimize energy levels, especially for boosting <em>V</em><sub>oc</sub>.</p></div>","PeriodicalId":399,"journal":{"name":"Organic Electronics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141729392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-16DOI: 10.1016/j.orgel.2024.107096
Solution-processed organic light-emitting diodes (OLEDs) remain a reliable approach towards large-area and flexible display devices, but also hold higher requirement on luminescent materials. It is still challenge to develop emitting layers with great solution-processable property and excellent luminous behavior, and especially difficult for non-doped emitting materials. In this work, a TADF emitter, namely 2,3,5,6-tetrakis(4-([1,1':3′,1″-terphenyl]-5′-yl)-9H-carbazol-9-yl)benzonitrile (3Ph-4CzBN), was designed and synthesized by introducing the steric-hindrance triphenyl unit to 2,3,5,6-tetrakis(carbazol-9-yl) benzonitrile (4CzBN) which is usually applied to vacuum evaporation. The incorporation of triphenyl groups significantly increased the molecule weight, thereby rendering 3Ph-4CzBN suitable for solution-processed OLEDs. Meanwhile, 3Ph-4CzBN exhibited two-fold of photoluminescence quantum yield values in pure film than 4CzBN, indicating fluorescence quenching was relatively suppressed by steric groups. The solution-processed OLEDs employed 3Ph-4CzBN as non-doped emitting layer, achieved a maximum external quantum efficiency of 12.8 %, as well as current efficiency and power efficiency up to 34.2 cd A−1 and 23.9 lm W−1, respectively.
{"title":"Introducing steric groups to thermally activated delayed fluorescence emitter for constructing efficient non-doped solution-processed organic light-emitting diodes","authors":"","doi":"10.1016/j.orgel.2024.107096","DOIUrl":"10.1016/j.orgel.2024.107096","url":null,"abstract":"<div><p>Solution-processed organic light-emitting diodes (OLEDs) remain a reliable approach towards large-area and flexible display devices, but also hold higher requirement on luminescent materials. It is still challenge to develop emitting layers with great solution-processable property and excellent luminous behavior, and especially difficult for non-doped emitting materials. In this work, a TADF emitter, namely 2,3,5,6-tetrakis(4-([1,1':3′,1″-terphenyl]-5′-yl)-9H-carbazol-9-yl)benzonitrile (<strong>3Ph-4CzBN)</strong>, was designed and synthesized by introducing the steric-hindrance triphenyl unit to 2,3,5,6-tetrakis(carbazol-9-yl) benzonitrile (4CzBN) which is usually applied to vacuum evaporation. The incorporation of triphenyl groups significantly increased the molecule weight, thereby rendering <strong>3Ph-4CzBN</strong> suitable for solution-processed OLEDs. Meanwhile, <strong>3Ph-4CzBN</strong> exhibited two-fold of photoluminescence quantum yield values in pure film than 4CzBN, indicating fluorescence quenching was relatively suppressed by steric groups. The solution-processed OLEDs employed <strong>3Ph-4CzBN</strong> as non-doped emitting layer, achieved a maximum external quantum efficiency of 12.8 %, as well as current efficiency and power efficiency up to 34.2 cd A<sup>−1</sup> and 23.9 lm W<sup>−1</sup>, respectively.</p></div>","PeriodicalId":399,"journal":{"name":"Organic Electronics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141638268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-16DOI: 10.1016/j.orgel.2024.107095
Multi-resonance thermally activated delayed fluorescence (MR-TADF) molecules charactering large emission oscillator strengths, effective reverse intersystem crossing (RISC), and narrow emission spectral width, have great potential as laser materials. We propose a molecular descriptor for quick screening MR-TADF molecules as laser candidate materials, A = , namely, the product of singlet-triplet energy gap and the optical pumping net stimulated emission cross section. These quantities can be calculated by combining quantum chemistry package Gaussian and our own MOMAP program. Through extensive computations benchmarked with existing experiments, we suggest that A value should be larger than 0.311 ⨉ 10−17 cm2 eV for promising lasing molecules. We virtually designed 119 molecules with MR-TADF property, and based on our theoretical protocol by considering descriptor A, we are able to select 10 molecules as lasing molecules. We then further screen out 2 molecules through analyzing the spectral overlap, indicating that only eight molecules are prospective candidates for laser materials. Particularly, we find that ADBNA-Me-BPy molecule possesses large radiative decay rate and large reverse intersystem crossing rate, 1.90 × 106 s−1 and 1.01 × 108 s−1, respectively, implying a low lasing threshold, promising for electrically pumped lasing.
{"title":"Computational screening of multi-resonance thermally activated delayed fluorescence (MR-TADF) molecules for lasing application","authors":"","doi":"10.1016/j.orgel.2024.107095","DOIUrl":"10.1016/j.orgel.2024.107095","url":null,"abstract":"<div><p>Multi-resonance thermally activated delayed fluorescence (MR-TADF) molecules charactering large emission oscillator strengths, effective reverse intersystem crossing (RISC), and narrow emission spectral width, have great potential as laser materials. We propose a molecular descriptor for quick screening MR-TADF molecules as laser candidate materials, <em>A =</em> <span><math><mrow><msub><mrow><mo>Δ</mo><mi>E</mi></mrow><mtext>ST</mtext></msub><msubsup><mi>σ</mi><mtext>eff</mtext><mrow><mtext>net</mtext><mo>,</mo><mtext>opt</mtext></mrow></msubsup></mrow></math></span>, namely, the product of singlet-triplet energy gap and the optical pumping net stimulated emission cross section. These quantities can be calculated by combining quantum chemistry package Gaussian and our own MOMAP program. Through extensive computations benchmarked with existing experiments, we suggest that <em>A</em> value should be larger than 0.311 ⨉ 10<sup>−17</sup> cm<sup>2</sup> eV for promising lasing molecules. We virtually designed 119 molecules with MR-TADF property, and based on our theoretical protocol by considering descriptor <em>A</em>, we are able to select 10 molecules as lasing molecules. We then further screen out 2 molecules through analyzing the spectral overlap, indicating that only eight molecules are prospective candidates for laser materials. Particularly, we find that ADBNA-Me-BPy molecule possesses large radiative decay rate and large reverse intersystem crossing rate, 1.90 × 10<sup>6</sup> s<sup>−1</sup> and 1.01 × 10<sup>8</sup> s<sup>−1</sup>, respectively, implying a low lasing threshold, promising for electrically pumped lasing.</p></div>","PeriodicalId":399,"journal":{"name":"Organic Electronics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141638269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-06DOI: 10.1016/j.orgel.2024.107090
Hongying Qiu, Shuqiong Lan, Qiubao Lin, Huili Zhu, Wenliang Liao, Lan Yang
Artificial synaptic devices, which are the basic units of neuromorphic computing systems, can perform signal processing with low power consumption. Organic synaptic transistors have attracted significant attention owing to their lightweight and good compatibility with flexible substrates. As per the current state of research both domestically and internationally, the majority of the existing organic synaptic transistors are based on floating gate structures, electret configurations, ferroelectric types. Furthermore, additional capture layers are required for the preparation of these devices. Two-dimensional MXenes have great potential in the preparation of synaptic transistors owing to their efficient multiple energy storage capabilities, excellent metallic conductivity, abundant surface functional groups, hydrophilicity, and layered structure. Therefore, high-performance synaptic transistors based on the two-dimensional material MXene were developed in this study. These transistors not only exhibited excellent memory performance with a memory window above 20 V, but also successfully simulated typical synaptic behaviors, including excitatory postsynaptic current/inhibitory postsynaptic current (EPSC/IPSC), paired-pulse facilitation/paired-pulse depression (PPF/PPD), and long-term plasticity (LTP). Synaptic transistors based on MXenes represent a promising approach for the preparation of high-performance organic synaptic transistors.
{"title":"Simulation of neural functions based on organic semiconductor/MXene synaptic transistors","authors":"Hongying Qiu, Shuqiong Lan, Qiubao Lin, Huili Zhu, Wenliang Liao, Lan Yang","doi":"10.1016/j.orgel.2024.107090","DOIUrl":"https://doi.org/10.1016/j.orgel.2024.107090","url":null,"abstract":"<div><p>Artificial synaptic devices, which are the basic units of neuromorphic computing systems, can perform signal processing with low power consumption. Organic synaptic transistors have attracted significant attention owing to their lightweight and good compatibility with flexible substrates. As per the current state of research both domestically and internationally, the majority of the existing organic synaptic transistors are based on floating gate structures, electret configurations, ferroelectric types. Furthermore, additional capture layers are required for the preparation of these devices. Two-dimensional MXenes have great potential in the preparation of synaptic transistors owing to their efficient multiple energy storage capabilities, excellent metallic conductivity, abundant surface functional groups, hydrophilicity, and layered structure. Therefore, high-performance synaptic transistors based on the two-dimensional material MXene were developed in this study. These transistors not only exhibited excellent memory performance with a memory window above 20 V, but also successfully simulated typical synaptic behaviors, including excitatory postsynaptic current/inhibitory postsynaptic current (EPSC/IPSC), paired-pulse facilitation/paired-pulse depression (PPF/PPD), and long-term plasticity (LTP). Synaptic transistors based on MXenes represent a promising approach for the preparation of high-performance organic synaptic transistors.</p></div>","PeriodicalId":399,"journal":{"name":"Organic Electronics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141583348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-06DOI: 10.1016/j.orgel.2024.107089
Mehr Khalid Rahmani , Sobia Ali Khan , Dae-Myeong Geum , Hyuntak Jeon , Seong Yeon Park , Changhun Yun , Moon Hee Kang
Organic nonvolatile memory devices have garnered significant attention as next-generation electrical memory units owing to their potential for low-cost and straightforward fabrication through a solution process. In this study, we successfully fabricated fully solution-processed organic resistive random access memory (RRAM) devices using poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as the resistive switching (RS) layer, with poly(3,4-ethylene-dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) employed as the top electrode. Additionally, to enhance performance further, a polyethyleneimine (PEIE) interlayer was introduced between the bottom electrode and the P3HT:PCBM RS layer. The resulting organic RRAM devices with the PEIE interlayer exhibited bipolar resistive switching, with improved endurance increasing from 50 to 100 cycles, a retention time of 103 s, and a low SET voltage of 0.7 V. The organic RRAM devices featuring the PEIE interlayer demonstrated superior RS performance attributed to the higher Schottky barrier at the interface between the bottom electrode and the active switching layer, creating an asymmetric structure. I–V curve fitting confirmed that the potential switching mechanism involved Schottky emission in the high-resistance state and Ohmic conduction in the low-resistance state. Our findings suggest that organic RRAM devices with a PEIE interlayer hold promise for stable nonvolatile memory applications.
{"title":"Enhanced resistive switching behaviors of organic resistive random access memory devices by adding polyethyleneimine interlayer","authors":"Mehr Khalid Rahmani , Sobia Ali Khan , Dae-Myeong Geum , Hyuntak Jeon , Seong Yeon Park , Changhun Yun , Moon Hee Kang","doi":"10.1016/j.orgel.2024.107089","DOIUrl":"https://doi.org/10.1016/j.orgel.2024.107089","url":null,"abstract":"<div><p>Organic nonvolatile memory devices have garnered significant attention as next-generation electrical memory units owing to their potential for low-cost and straightforward fabrication through a solution process. In this study, we successfully fabricated fully solution-processed organic resistive random access memory (RRAM) devices using poly(3-hexylthiophene-2,5-diyl) <u>(P3HT)</u> and [6,6]-phenyl-C61-butyric acid methyl ester <u>(PCBM)</u> as the resistive switching (RS) layer, with poly(3,4-ethylene-dioxythiophene):poly(styrene sulfonate) <u>(PEDOT:PSS)</u> employed as the top electrode. Additionally, to enhance performance further, a polyethyleneimine (PEIE) interlayer was introduced between the bottom electrode and the P3HT:PCBM RS layer. The resulting organic RRAM devices with the PEIE interlayer exhibited bipolar resistive switching, with improved endurance increasing from 50 to 100 cycles, a retention time of 10<sup>3</sup> s, and a low SET voltage of 0.7 V. The organic RRAM devices featuring the PEIE interlayer demonstrated superior RS performance attributed to the higher Schottky barrier at the interface between the bottom electrode and the active switching layer, creating an asymmetric structure. I–V curve fitting confirmed that the potential switching mechanism involved Schottky emission in the high-resistance state and Ohmic conduction in the low-resistance state. Our findings suggest that organic RRAM devices with a PEIE interlayer hold promise for stable nonvolatile memory applications.</p></div>","PeriodicalId":399,"journal":{"name":"Organic Electronics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141605312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1016/j.orgel.2024.107088
Zhao Hao, Yi Li, Yuanjian Deng, Zehua Chen, Jie Liang, Xiuzhen Lu, Jianhua Zhang
A new class of flexible X-ray sensor in which there is a vertical structure with the active layer of minor 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) blending into styrene-ethylene-butadiene-styrene (SEBS) has been developed. The minor TIPS-pentacene to enhance the sensitivity of 1137.2 μCGyair−1 cm−2 and low detection limit of 47.91 nGyair s−1 because of the higher attenuation coefficient and photocurrent gain effect in the hybrid active layer. The stability and flexibility of this organic detector are attributed to the plasticity of SEBS and encapsulation of TIPS-pentacene. This work highlights the potential exploitation of high-performance future innovative flexible and highly sensitive direct X-ray detectors.
一种新型柔性 X 射线传感器已经研制成功,这种传感器采用垂直结构,其活性层是在苯乙烯-乙烯-丁二烯-苯乙烯(SEBS)中掺入次要的 6,13-双(三异丙基硅烷基乙炔基)并五苯(TIPS-pentacene)。由于混合活性层中较高的衰减系数和光电流增益效应,次要的 TIPS-pentacene 提高了 1137.2 μCGyair-1 cm-2 的灵敏度和 47.91 nGyair s-1 的低检测限。这种有机探测器的稳定性和灵活性归功于 SEBS 的可塑性和 TIPS-pentacene 的封装。这项研究成果凸显了未来高性能创新型柔性高灵敏度直接 X 射线探测器的开发潜力。
{"title":"High sensitivity flexible organic X-ray detectors with minor TIPS-pentacene/insulator polymer blend active layer","authors":"Zhao Hao, Yi Li, Yuanjian Deng, Zehua Chen, Jie Liang, Xiuzhen Lu, Jianhua Zhang","doi":"10.1016/j.orgel.2024.107088","DOIUrl":"https://doi.org/10.1016/j.orgel.2024.107088","url":null,"abstract":"<div><p>A new class of flexible X-ray sensor in which there is a vertical structure with the active layer of minor 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) blending into styrene-ethylene-butadiene-styrene (SEBS) has been developed. The minor TIPS-pentacene to enhance the sensitivity of 1137.2 μCGy<sub>air</sub><sup>−1</sup> cm<sup>−2</sup> and low detection limit of 47.91 nGy<sub>air</sub> s<sup>−1</sup> because of the higher attenuation coefficient and photocurrent gain effect in the hybrid active layer. The stability and flexibility of this organic detector are attributed to the plasticity of SEBS and encapsulation of TIPS-pentacene. This work highlights the potential exploitation of high-performance future innovative flexible and highly sensitive direct X-ray detectors.</p></div>","PeriodicalId":399,"journal":{"name":"Organic Electronics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141542398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-28DOI: 10.1016/j.orgel.2024.107086
Aziz Khan , Xing Chen , Man-Keung Fung , Zhiming Wang
The universal host material with boron acceptor core structure is exceptionally sparse to be designed for red, green, and blue in efficient phosphorescent organic light emitting diodes (PhOLEDs) accompanying white OLEDs, possessing indistinguishable device feature. Herein, two boron acceptors spiro-host materials namely 1'-(4-(dimesitylboranyl)phenyl)-10-phenyl-10H-spiro[acridine-9,9′-fluorene] (TPA-PBM) and 1-(4-(dimesitylboranyl)phenyl)-3′,6′-dimethylspiro[fluorene-9,8′-indolo[3,2,1-de]acridine] (2MeCz-PBM) were designed and synthesized. The designed rigid donor strategy exhibited good device performance among the reported boron donor-spiro-acceptor (D-spiro-A) skeleton for organic light emitting diodes (OLEDs). In particular, we fabricate RGB three-color phosphorescent OLEDs based on TPA-PBM and 2MeCz-PBM. The red devices exhibit a maximum external quantum efficiency (EQE) of nearly 28 % (26.8 % for TPA-PBM and 27.5 % for 2MeCz-PBM), with an electroluminescence spectrum at 608 nm. The green/blue devices obtain maximum EQEs of 21.2 %/15.3 % and 21.8 % 17.3 %, for TPA-PBM and 2MeCz-PBM, respectively. Furthermore, green devices display an extremely low efficiency roll-off with decreasing 1 % and 3 % at luminance of 5000 cd m−2. Additionally, the two-color white OLED using 2MeCz-PBM exhibits EQEmax and PEmax are 24.5 % and 62.9 lm W−1 respectively, the EQE remain 23.8 % at commercial lighting brightness of 1000 cd m−2. The WOLED also shows a stable white spectrum with CIE varying range of (0.41, 0.47) to (0.39, 0.46) at 100 cd m−2 to 15000 cd m−2. All obtained results confirmed that our targeted molecules have advantage of carrier balance and efficient charge recombination, which might replace many other commercial host materials.
{"title":"Improving efficiency in RGB phosphorescent and white organic light emitting diodes via donor-spiro-boron acceptor host materials","authors":"Aziz Khan , Xing Chen , Man-Keung Fung , Zhiming Wang","doi":"10.1016/j.orgel.2024.107086","DOIUrl":"https://doi.org/10.1016/j.orgel.2024.107086","url":null,"abstract":"<div><p>The universal host material with boron acceptor core structure is exceptionally sparse to be designed for red, green, and blue in efficient phosphorescent organic light emitting diodes (PhOLEDs) accompanying white OLEDs, possessing indistinguishable device feature. Herein, two boron acceptors spiro-host materials namely 1'-(4-(dimesitylboranyl)phenyl)-10-phenyl-10H-spiro[acridine-9,9′-fluorene] <strong>(TPA-PBM)</strong> and 1-(4-(dimesitylboranyl)phenyl)-3′,6′-dimethylspiro[fluorene-9,8′-indolo[3,2,1-de]acridine] (<strong>2MeCz-PBM)</strong> were designed and synthesized. The designed rigid donor strategy exhibited good device performance among the reported boron donor-spiro-acceptor (D-spiro-A) skeleton for organic light emitting diodes (OLEDs). In particular, we fabricate RGB three-color phosphorescent OLEDs based on <strong>TPA-PBM</strong> and <strong>2MeCz-PBM.</strong> The red devices exhibit a maximum external quantum efficiency (EQE) of nearly 28 % (26.8 % for <strong>TPA-PBM</strong> and 27.5 % for <strong>2MeCz-PBM</strong>), with an electroluminescence spectrum at 608 nm. The green/blue devices obtain maximum EQEs of 21.2 %/15.3 % and 21.8 % 17.3 %, for <strong>TPA-PBM</strong> and <strong>2MeCz-PBM</strong>, respectively. Furthermore, green devices display an extremely low efficiency roll-off with decreasing 1 % and 3 % at luminance of 5000 cd m<sup>−2</sup>. Additionally, the two-color white OLED using <strong>2MeCz-PBM</strong> exhibits EQE<sub>max</sub> and PE<sub>max</sub> are 24.5 % and 62.9 lm W<sup>−1</sup> respectively, the EQE remain 23.8 % at commercial lighting brightness of 1000 cd m<sup>−2</sup>. The WOLED also shows a stable white spectrum with CIE varying range of (0.41, 0.47) to (0.39, 0.46) at 100 cd m<sup>−2</sup> to 15000 cd m<sup>−2</sup>. All obtained results confirmed that our targeted molecules have advantage of carrier balance and efficient charge recombination, which might replace many other commercial host materials.</p></div>","PeriodicalId":399,"journal":{"name":"Organic Electronics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141485821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-28DOI: 10.1016/j.orgel.2024.107087
Atefeh Ghorbani, Hany Aziz
ZnMgO nanoparticles (NPs) are being increasingly used as the electron transport layer (ETL) in state-of-the-art quantum-dot light-emitting devices (QLEDs) instead of ZnO. However, the impact of ZnMgO on the luminescence properties of quantum dots (QDs) is much less understood. Here, we compare ZnMgO and ZnO NPs for their quenching effect on Cd-based QDs photoluminescence (PL), immediately and over time. Time-resolved photoluminescence (TRPL) and steady-state PL results show that ZnMgO NPs decreases the QDs’ luminescence more than ZnO NPs and that the behavior continues progressively over time. The surface topography of the samples containing different ETLs is studied using atomic force microscopy (AFM) and optical PL images. Additionally, time of flight secondary ion mass spectroscopy (TOF-SIMS) measurements are conducted to investigate the potential diffusion of some species from ETL into the QDs layer. The results confirm that morphological changes and out-diffusion of some species from the ZnMgO layer can likely play a role in the QDs PL quenching. This study sheds light on the limitations of ZnMgO for the long-term stability of QLEDs, specifically for blue QLEDs where using ZnMgO is essential for efficient electron injection.
{"title":"Progressive quenching of luminescence from quantum dot thin films in proximity with ZnMgO in unencapsulated stacks","authors":"Atefeh Ghorbani, Hany Aziz","doi":"10.1016/j.orgel.2024.107087","DOIUrl":"https://doi.org/10.1016/j.orgel.2024.107087","url":null,"abstract":"<div><p>ZnMgO nanoparticles (NPs) are being increasingly used as the electron transport layer (ETL) in state-of-the-art quantum-dot light-emitting devices (QLEDs) instead of ZnO. However, the impact of ZnMgO on the luminescence properties of quantum dots (QDs) is much less understood. Here, we compare ZnMgO and ZnO NPs for their quenching effect on Cd-based QDs photoluminescence (PL), immediately and over time. Time-resolved photoluminescence (TRPL) and steady-state PL results show that ZnMgO NPs decreases the QDs’ luminescence more than ZnO NPs and that the behavior continues progressively over time. The surface topography of the samples containing different ETLs is studied using atomic force microscopy (AFM) and optical PL images. Additionally, time of flight secondary ion mass spectroscopy (TOF-SIMS) measurements are conducted to investigate the potential diffusion of some species from ETL into the QDs layer. The results confirm that morphological changes and out-diffusion of some species from the ZnMgO layer can likely play a role in the QDs PL quenching. This study sheds light on the limitations of ZnMgO for the long-term stability of QLEDs, specifically for blue QLEDs where using ZnMgO is essential for efficient electron injection.</p></div>","PeriodicalId":399,"journal":{"name":"Organic Electronics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1566119924000983/pdfft?md5=727a6e599d1c56c4cc38163fa67ddb44&pid=1-s2.0-S1566119924000983-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141542397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-25DOI: 10.1016/j.orgel.2024.107085
Hengwei Tian , Xuming Zhuang , Zhi-Ping Yan , Hai Bi , Zhiqiang Li , Yue Wang , Yanping Huo
The slow reverse intersystem crossing (RISC) rate in thermally activated delayed fluorescence (TADF) emitters result in extended exciton lifetime and pronounced efficiency loss at high luminance level. To address this limitation, we have developed and characterized a series of novel compounds featuring triazine cores substituted with tert-butyl carbazole moieties at various positions and quantities. The objective here is to fine-tune the charge transfer properties, thereby enhancing the efficiency of the RISC process. Our studies reveal that through-space charge transfer is more effective than long-range through-bond charge transfer in minimizing the singlet-triplet energy gap and accelerating RISC. The optimized compound, 4tCzTrz, exhibits an exceptionally fast RISC rate of 1.02 × 107 s−1 and a high photoluminescence quantum yield of up to 100 %. Solution-processed organic light-emitting diodes (OLEDs) incorporating this molecule have achieved outstanding maximum external quantum efficiencies of around 20 %, whether used as an emitter directly or as a sensitizer to boost overall emission efficiency.
{"title":"Manipulating the photophysical properties of multi-donor molecules for fast reverse intersystem crossing in solution-processed OLED devices","authors":"Hengwei Tian , Xuming Zhuang , Zhi-Ping Yan , Hai Bi , Zhiqiang Li , Yue Wang , Yanping Huo","doi":"10.1016/j.orgel.2024.107085","DOIUrl":"https://doi.org/10.1016/j.orgel.2024.107085","url":null,"abstract":"<div><p>The slow reverse intersystem crossing (RISC) rate in thermally activated delayed fluorescence (TADF) emitters result in extended exciton lifetime and pronounced efficiency loss at high luminance level. To address this limitation, we have developed and characterized a series of novel compounds featuring triazine cores substituted with <em>tert</em>-butyl carbazole moieties at various positions and quantities. The objective here is to fine-tune the charge transfer properties, thereby enhancing the efficiency of the RISC process. Our studies reveal that through-space charge transfer is more effective than long-range through-bond charge transfer in minimizing the singlet-triplet energy gap and accelerating RISC. The optimized compound, <strong>4tCzTrz</strong>, exhibits an exceptionally fast RISC rate of 1.02 × 10<sup>7</sup> s<sup>−1</sup> and a high photoluminescence quantum yield of up to 100 %. Solution-processed organic light-emitting diodes (OLEDs) incorporating this molecule have achieved outstanding maximum external quantum efficiencies of around 20 %, whether used as an emitter directly or as a sensitizer to boost overall emission efficiency.</p></div>","PeriodicalId":399,"journal":{"name":"Organic Electronics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141485822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}