A. Mischok, Sabina Hillebrandt, Seonil Kwon, M. Gather
Organic materials are good absorbers for optical filters and good emitters for OLEDs, largely due to their high oscillator strengths. However, this comes at the cost of broad spectral linewidths, which limits the usefulness of absorptive filters and restricts colour purity in displays. Interference-based structures offer narrower spectra but show an intrinsic and often substantial angle dependence. Here, we overcome these limitations by combining the concepts of absorption and interference. Introducing absorbers into a microcavity leads to a coupled polariton state that inherits the low dispersion of the material exciton and the narrow linewidth of the cavity mode and thus enables line-filters with record spectral discrimination and angular stability (e.g., FWHM 10%, FWHM <20nm, angle shift <10nm @60° tilt).
{"title":"Optical filters and OLEDs with narrow linewidth and low angle dispersion via strong light-matter coupling","authors":"A. Mischok, Sabina Hillebrandt, Seonil Kwon, M. Gather","doi":"10.1117/12.2595355","DOIUrl":"https://doi.org/10.1117/12.2595355","url":null,"abstract":"Organic materials are good absorbers for optical filters and good emitters for OLEDs, largely due to their high oscillator strengths. However, this comes at the cost of broad spectral linewidths, which limits the usefulness of absorptive filters and restricts colour purity in displays. Interference-based structures offer narrower spectra but show an intrinsic and often substantial angle dependence. Here, we overcome these limitations by combining the concepts of absorption and interference. Introducing absorbers into a microcavity leads to a coupled polariton state that inherits the low dispersion of the material exciton and the narrow linewidth of the cavity mode and thus enables line-filters with record spectral discrimination and angular stability (e.g., FWHM 10%, FWHM <20nm, angle shift <10nm @60° tilt).","PeriodicalId":19672,"journal":{"name":"Organic and Hybrid Light Emitting Materials and Devices XXV","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90492817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Iakov Goldberg, Karim Elkhouly, W. Qiu, Nirav Annavarapu, R. Gehlhaar, C. Rolin, T. Ke, J. Genoe, P. Heremans
We present variable-size circular micro methylammonium lead iodide PeLEDs and systematically examine their performance in moderate and high current density regimes. We demonstrate the beneficial influence of device downscaling on the internal heat generation and its positive impact on lifetime. For micron size glass-based devices with external quantum efficiencies (EQE) of around 5.5 %, we achieve a T50 > 5 h at 1000 mA·cm-2 at room temperature. The scaling-down approach and device architecture optimizations allowed for pulsed driving of the PeLEDs as short as 250 ns, reaching exceptionally large current densities above 5 kA·cm-2 and radiance values above 30000 W·m-2·sr-1.
{"title":"Record operational stability and lasing-level current densities enabled by incremental PeLED downscaling","authors":"Iakov Goldberg, Karim Elkhouly, W. Qiu, Nirav Annavarapu, R. Gehlhaar, C. Rolin, T. Ke, J. Genoe, P. Heremans","doi":"10.1117/12.2593010","DOIUrl":"https://doi.org/10.1117/12.2593010","url":null,"abstract":"We present variable-size circular micro methylammonium lead iodide PeLEDs and systematically examine their performance in moderate and high current density regimes. We demonstrate the beneficial influence of device downscaling on the internal heat generation and its positive impact on lifetime. For micron size glass-based devices with external quantum efficiencies (EQE) of around 5.5 %, we achieve a T50 > 5 h at 1000 mA·cm-2 at room temperature. The scaling-down approach and device architecture optimizations allowed for pulsed driving of the PeLEDs as short as 250 ns, reaching exceptionally large current densities above 5 kA·cm-2 and radiance values above 30000 W·m-2·sr-1.","PeriodicalId":19672,"journal":{"name":"Organic and Hybrid Light Emitting Materials and Devices XXV","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87390321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sangshin Park, Hyukmin Kwon, Seokwoo Kang, Sunwoo Park, Jongwook Park
Highly stable perovskite quantum dots (PeQDs) are developed using excess Zn precursor and trioctylphosphine‐oxide (TOPO). They not only have high quantum efficiency and sharp full width at half maximum values (15–30 nm) but also have improved long‐term stability at high temperature. They have EQE (%) and current efficiency (Cd A−1) of (7.12%, 9.93 Cd A−1) for red, (6.06%, 32.5 Cd A−1) for green, and (0.56%, 0.88 Cd A−1) for blue‐emitting devices, respectively. Also, a new hole-transporting material, poly-2-(9Hcarbazol-9-yl)-5-(4-vinylphenyl)-5H-benzo[b]carbazole (PBCZCZ), was developed for perovskite light-emitting diodes (PeLEDs). The EQE of the green PeLEDs using PBCZCZ was about 2.5 times higher and that of the sky-blue PeLEDs was about 3 times higher than the device made with the commercial HTL of PVK. The operational device lifetimes of the green and sky-blue PeLEDs made with PBCZCZ were about 4.1 and 4.8 times higher than the PVK-containing device.
利用过量Zn前驱体和三辛基膦氧化物(TOPO)制备了高稳定性的钙钛矿量子点(PeQDs)。它们不仅具有高量子效率和一半最大值(15-30 nm)的锐全宽度，而且还具有在高温下的长期稳定性。它们的EQE(%)和电流效率(Cd A−1)分别为红色(7.12%，9.93 Cd A−1)，绿色(6.06%，32.5 Cd A−1)，蓝色发射器件(0.56%，0.88 Cd A−1)。此外，还制备了一种用于钙钛矿发光二极管(PeLEDs)的新型空穴传输材料聚2-(9Hcarbazol-9-yl)-5-(4-乙烯基苯基)- 5h -苯并[b]咔唑(PBCZCZ)。使用PBCZCZ的绿色pled的EQE比使用PVK的商用html制作的器件高约2.5倍，天蓝色pled的EQE高约3倍。用PBCZCZ制成的绿色和天蓝色ped的工作寿命分别比含pvk的器件高4.1和4.8倍。
{"title":"Stable all‐inorganic perovskite quantum dots using a ZnX2‐trioctylphosphine‐oxide and a new hole transporting polymer in PeLEDs","authors":"Sangshin Park, Hyukmin Kwon, Seokwoo Kang, Sunwoo Park, Jongwook Park","doi":"10.1117/12.2593786","DOIUrl":"https://doi.org/10.1117/12.2593786","url":null,"abstract":"Highly stable perovskite quantum dots (PeQDs) are developed using excess Zn precursor and trioctylphosphine‐oxide (TOPO). They not only have high quantum efficiency and sharp full width at half maximum values (15–30 nm) but also have improved long‐term stability at high temperature. They have EQE (%) and current efficiency (Cd A−1) of (7.12%, 9.93 Cd A−1) for red, (6.06%, 32.5 Cd A−1) for green, and (0.56%, 0.88 Cd A−1) for blue‐emitting devices, respectively. Also, a new hole-transporting material, poly-2-(9Hcarbazol-9-yl)-5-(4-vinylphenyl)-5H-benzo[b]carbazole (PBCZCZ), was developed for perovskite light-emitting diodes (PeLEDs). The EQE of the green PeLEDs using PBCZCZ was about 2.5 times higher and that of the sky-blue PeLEDs was about 3 times higher than the device made with the commercial HTL of PVK. The operational device lifetimes of the green and sky-blue PeLEDs made with PBCZCZ were about 4.1 and 4.8 times higher than the PVK-containing device.","PeriodicalId":19672,"journal":{"name":"Organic and Hybrid Light Emitting Materials and Devices XXV","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74115116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this talk, we will firstly present a strategy to realize deep blue TADF OLEDs with the EQE of 28% and CIE y value of 0.09 by narrowing the emission spectrum of blue TADF emitters along with high horizontal emitting dipole orientation. Secondly we will present deep blue OLEDs utilizing TTA process based on anthracene derivatives. For blue-emitting anthracene derivatives, the theoretical maximum contribution of TTA to emissive singlet excitons is considered to be 15%, which is insufficient for high-efficiency fluorescent devices. In this study, we realised a TTA contribution of nearly 25% using an anthracene derivative, breaking the theoretical limit. As a result, efficient deep-blue TTA fluorescent devices were developed, which exhibited maximum external quantum efficiencies of 10.2%. A theoretical model will be presented to explain the experimental results considering both the TTA and RISC to a singlet state from a high level triplet state formed by the TTA process.
{"title":"High efficiency deep blue OLEDs","authors":"Jang‐Joo Kim, Hyun-Kook Lim, Yun‐Hi Kim","doi":"10.1117/12.2595922","DOIUrl":"https://doi.org/10.1117/12.2595922","url":null,"abstract":"In this talk, we will firstly present a strategy to realize deep blue TADF OLEDs with the EQE of 28% and CIE y value of 0.09 by narrowing the emission spectrum of blue TADF emitters along with high horizontal emitting dipole orientation. Secondly we will present deep blue OLEDs utilizing TTA process based on anthracene derivatives. For blue-emitting anthracene derivatives, the theoretical maximum contribution of TTA to emissive singlet excitons is considered to be 15%, which is insufficient for high-efficiency fluorescent devices. In this study, we realised a TTA contribution of nearly 25% using an anthracene derivative, breaking the theoretical limit. As a result, efficient deep-blue TTA fluorescent devices were developed, which exhibited maximum external quantum efficiencies of 10.2%. A theoretical model will be presented to explain the experimental results considering both the TTA and RISC to a singlet state from a high level triplet state formed by the TTA process.","PeriodicalId":19672,"journal":{"name":"Organic and Hybrid Light Emitting Materials and Devices XXV","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82183095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper we introduce a new light emitting device where phosphorescent emitters are intentionally coupled to the surface plasmon mode of a nearby metal electrode for decay rate enhancement. This energy is subsequently converted to photons in free space via a nanoparticle-based out-coupling scheme allowing us to harvest both efficiency and stability gains. Compared to a reference OLED based on conventional device design, our new architecture achieves a two-fold increase in operational stability at the same brightness while simultaneously outcoupling 8% of photons from the device.
{"title":"Increasing OLED stability: Plasmonic PHOLED","authors":"Nicholas J. Thompson","doi":"10.1117/12.2595069","DOIUrl":"https://doi.org/10.1117/12.2595069","url":null,"abstract":"In this paper we introduce a new light emitting device where phosphorescent emitters are intentionally coupled to the surface plasmon mode of a nearby metal electrode for decay rate enhancement. This energy is subsequently converted to photons in free space via a nanoparticle-based out-coupling scheme allowing us to harvest both efficiency and stability gains. Compared to a reference OLED based on conventional device design, our new architecture achieves a two-fold increase in operational stability at the same brightness while simultaneously outcoupling 8% of photons from the device.","PeriodicalId":19672,"journal":{"name":"Organic and Hybrid Light Emitting Materials and Devices XXV","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90338208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, we investigated the methods for prolonged lifetime in the CsPbX3 (X: Cl, Br, I) structured perovskite materials. First, the changes in structural and optical properties were compared by doping Ni in the CsPbBr3 quantum dots (QDs). The steady-state photoluminescence (PL) intensity of Ni-doped QDs shows 3.8 times increase comparing with undoped QDs. CsPbBr3 without nickel had a quantum efficiency of only 56.7 %, whereas CsPbBr3 doped with nickel had a quantum efficiency of 82.9 %. It was found that the doped divalent element acts as a defect in the perovskite structure, reducing the recombination rate of electrons and holes. After 48 hours UV-light irradiation, PL intensity of CsPbBr3 decreased about 70 % while that of Ni-substituted CsPbBr3 QDs decreased only 18 %, indicating the prolonged stability against UV-light irradiation. Furthermore, Ni-substituted CsPbBr3 QDs shows higher stability against temperature and moisture. These results confirmed that Ni substitution method is effective to increase the stability of CsPbX3 QDs. Second, we used sulfuroleylamine (S-OLA) complex which was utilized to etch the defect-rich surface of the CsPbI3 QDs and then self-assembly to form a matrix outside the CsPbI3 QDs protected the QDs from environmental moisture and solar irradiation. The PL intensity of the CsPbI3 QDs increased by 21% of its initial value. There was a significant increase in the colloidal stability of the CsPbI3 QDs. The introduction of S-OLA induced the recovery of the lost photoluminescence of the nonluminous aged CsPbI3 QDs with time to 95% of that of the fresh QDs. Furthermore, the PL was maintained for one month. The increase in the stability and PL intensity are critical for realizing high-performance perovskite-QD-based devices. In this study, we investigated the methods for prolonged lifetime in the CsPbX3 (X: Cl, Br, I) structured perovskite materials. First, the changes in structural and optical properties were compared by doping Ni in the CsPbBr3 quantum dots (QDs). It was found that the doped divalent element acts as a defect in the perovskite structure, reducing the recombination rate of electrons and holes. Ni-substituted CsPbBr3 QDs shows higher stability against temperature and moisture. These results confirmed that Ni substitution method is effective to increase the stability of CsPbX3 QDs. Second, we used sulfuroleylamine (S-OLA) complex which was utilized to etch the defect-rich surface of the CsPbI3 QDs and then self-assembly to form a matrix outside the CsPbI3 QDs protected the QDs from environmental moisture and solar irradiation. The introduction of S-OLA induced the recovery of the lost photoluminescence of the nonluminous aged CsPbI3 QDs with time to 95% of that of the fresh QDs.
{"title":"Enhancing optical properties and stability of cesium lead halide quantum dots through nickel substitution and ligand change","authors":"S. Y. Kim, Ho Won Jang","doi":"10.1117/12.2594024","DOIUrl":"https://doi.org/10.1117/12.2594024","url":null,"abstract":"In this study, we investigated the methods for prolonged lifetime in the CsPbX3 (X: Cl, Br, I) structured perovskite materials. First, the changes in structural and optical properties were compared by doping Ni in the CsPbBr3 quantum dots (QDs). The steady-state photoluminescence (PL) intensity of Ni-doped QDs shows 3.8 times increase comparing with undoped QDs. CsPbBr3 without nickel had a quantum efficiency of only 56.7 %, whereas CsPbBr3 doped with nickel had a quantum efficiency of 82.9 %. It was found that the doped divalent element acts as a defect in the perovskite structure, reducing the recombination rate of electrons and holes. After 48 hours UV-light irradiation, PL intensity of CsPbBr3 decreased about 70 % while that of Ni-substituted CsPbBr3 QDs decreased only 18 %, indicating the prolonged stability against UV-light irradiation. Furthermore, Ni-substituted CsPbBr3 QDs shows higher stability against temperature and moisture. These results confirmed that Ni substitution method is effective to increase the stability of CsPbX3 QDs. Second, we used sulfuroleylamine (S-OLA) complex which was utilized to etch the defect-rich surface of the CsPbI3 QDs and then self-assembly to form a matrix outside the CsPbI3 QDs protected the QDs from environmental moisture and solar irradiation. The PL intensity of the CsPbI3 QDs increased by 21% of its initial value. There was a significant increase in the colloidal stability of the CsPbI3 QDs. The introduction of S-OLA induced the recovery of the lost photoluminescence of the nonluminous aged CsPbI3 QDs with time to 95% of that of the fresh QDs. Furthermore, the PL was maintained for one month. The increase in the stability and PL intensity are critical for realizing high-performance perovskite-QD-based devices.\u0000\u0000\u0000\u0000In this study, we investigated the methods for prolonged lifetime in the CsPbX3 (X: Cl, Br, I) structured perovskite materials. First, the changes in structural and optical properties were compared by doping Ni in the CsPbBr3 quantum dots (QDs). It was found that the doped divalent element acts as a defect in the perovskite structure, reducing the recombination rate of electrons and holes. Ni-substituted CsPbBr3 QDs shows higher stability against temperature and moisture. These results confirmed that Ni substitution method is effective to increase the stability of CsPbX3 QDs. Second, we used sulfuroleylamine (S-OLA) complex which was utilized to etch the defect-rich surface of the CsPbI3 QDs and then self-assembly to form a matrix outside the CsPbI3 QDs protected the QDs from environmental moisture and solar irradiation. The introduction of S-OLA induced the recovery of the lost photoluminescence of the nonluminous aged CsPbI3 QDs with time to 95% of that of the fresh QDs.","PeriodicalId":19672,"journal":{"name":"Organic and Hybrid Light Emitting Materials and Devices XXV","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73449937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Allegro, Yang Li, B. Richards, U. Paetzold, U. Lemmer, I. Howard
Continuous-wave (CW) lasing and amplified spontaneous emission (ASE) in 3D perovskite films has only been demonstrated at cryogenic temperatures. To understand the temperature limits of CW ASE, we investigate the carrier dynamics and determine the bimolecular and Auger recombination constants from 80 K up to 290 K in phase-stable triple cation perovskites. The bimolecular rate coefficient decreases with increasing temperature, whereas the Auger rate coefficient remains unchanged from cryogenic to room temperature. Above 250 K, at the ASE threshold carrier density, Auger recombination dominates the carrier dynamics and thus limits the lasing operation. At lower temperatures, below 250 K, the dominant effects leading to an increased ASE threshold with temperature are the decrease in the radiative recombination rate and the increased energy dilution of the charge carriers. Both of these effects reduce the rate of spontaneous emission into the ASE band.
{"title":"Temperature-dependent amplified spontaneous emission (ASE) threshold in phase-stable 3D perovskite films","authors":"I. Allegro, Yang Li, B. Richards, U. Paetzold, U. Lemmer, I. Howard","doi":"10.1117/12.2593037","DOIUrl":"https://doi.org/10.1117/12.2593037","url":null,"abstract":"Continuous-wave (CW) lasing and amplified spontaneous emission (ASE) in 3D perovskite films has only been demonstrated at cryogenic temperatures. To understand the temperature limits of CW ASE, we investigate the carrier dynamics and determine the bimolecular and Auger recombination constants from 80 K up to 290 K in phase-stable triple cation perovskites. The bimolecular rate coefficient decreases with increasing temperature, whereas the Auger rate coefficient remains unchanged from cryogenic to room temperature. Above 250 K, at the ASE threshold carrier density, Auger recombination dominates the carrier dynamics and thus limits the lasing operation. At lower temperatures, below 250 K, the dominant effects leading to an increased ASE threshold with temperature are the decrease in the radiative recombination rate and the increased energy dilution of the charge carriers. Both of these effects reduce the rate of spontaneous emission into the ASE band.","PeriodicalId":19672,"journal":{"name":"Organic and Hybrid Light Emitting Materials and Devices XXV","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74154738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Multiple resonance (MR) effect of boron and nitrogen/oxygen atoms induces the localization of the HOMO and LUMO on different atoms and minimizes their bonding/anti-bonding character; the resulting non-bonding molecular orbitals minimize the vibronic coupling and vibrational relaxation in the material, allowing the realization of an extremely sharp emission band and high PLQY. Moreover, the significant localization of the HOMO and LUMO reduces the energy gap between the S1 and T1 states, promoting the reverse intersystem crossing and thermally activated delayed fluorescence (TADF). Here, we present recent achievements in MR-TADF materials, construction of new core structures, and device applications.
{"title":"Development of multiple resonance effect-based TADF materials","authors":"T. Hatakeyama","doi":"10.1117/12.2595171","DOIUrl":"https://doi.org/10.1117/12.2595171","url":null,"abstract":"Multiple resonance (MR) effect of boron and nitrogen/oxygen atoms induces the localization of the HOMO and LUMO on different atoms and minimizes their bonding/anti-bonding character; the resulting non-bonding molecular orbitals minimize the vibronic coupling and vibrational relaxation in the material, allowing the realization of an extremely sharp emission band and high PLQY. Moreover, the significant localization of the HOMO and LUMO reduces the energy gap between the S1 and T1 states, promoting the reverse intersystem crossing and thermally activated delayed fluorescence (TADF). Here, we present recent achievements in MR-TADF materials, construction of new core structures, and device applications.","PeriodicalId":19672,"journal":{"name":"Organic and Hybrid Light Emitting Materials and Devices XXV","volume":"473 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79662805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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