Solar RRL最新文献

Tin oxide (SnO₂) has demonstrated significant potential as an electron transport layer (ETL) owing to its low-temperature processing in perovskite solar cells (PSCs). However, the poor energy-level alignment and the presence of interface defects between the SnO₂ and perovskite layer aggravate the power conversion efficiency (PCE) of the PSCs. Herein, heterovalent samarium cation (Sm³⁺) is deliberately doped into SnO₂, optimizing the energy-level alignment between SnO₂ and the perovskite layer, and effectively passivating the oxygen vacancy defects on the surface of SnO₂. Experimental and theoretical conclusions reveal that Sm-doping successfully passivates the defects in the ETL and improves the perovskite crystal quality, thereby reducing interface charge recombination, and enhancing electron extraction from perovskite to the SnO₂ layer. Consequently, the optimized Sm-doped SnO₂-based PSCs achieve a PCE of 24.10% with a V_OC of 1.174 V, negligible hysteresis, and improved durability under ambient conditions.

While state-of-the-art organic photovoltaics (OPVs) have been achieved by halogen modification strategies for active layer materials, the stability of these OPVs can be compromised by the presence of halogen ions at the interface and within the photoactive layer. Herein, halogen-free photoactive layer-based OPV cells are fabricated and systematically studied to understand and explore the working principle and potential of this class of OPV devices. For the first time, a champion efficiency of 13.12% is achieved for the inverted device (ITO/AZO/AL/MoO₃/Ag) based on the nonhalogenated photoactive layer PBDB-T:BTP-M. Superior metal electrode stability is confirmed for the unencapsulated PBDB-T:BTP-M devices aged at 85 °C in the air atmosphere compared to the halogenated PM6:Y6 devices. Specifically, better thermal stability is verified for the nonhalogenated device without 1-chloronaphthalene (1-CN) additive compared to the device with 1-CN additive, with 89% of the initial efficiency retained after being aged for 900 h at 85 °C in the N₂ atmosphere. These results evidence the halogen/halide impacts on device stability and demonstrate the potential for nonhalogenated OPVs to achieve efficient and stable performance, benefiting the development and practical application of this technology.

BiVO₄ has been widely concerned due to its great potential in photoelectrochemical (PEC) water splitting. However, low carrier mobilities and high recombination efficiency of photogenerated carriers impede its photocatalytic performance. Herein, an in situ PEC cyclic-voltammetry-induced surface reconstruction of BiVO₄ photoanodes (BVO pristine) is developed with significantly enhanced efficiency for solar water splitting. A series of in situ characterizations (including in situ X-ray diffraction, in situ Raman), together with electrochemical tests and density-functional theory calculations, reveal that during the photoelectrical activation process, the BVO pristine surfaces undergo a crystal plane reconstruction with greatly increased {040} crystal face to promote the separation of photogenerated carriers. In addition, abundant vanadium vacancies and oxygen vacancies are also introduced into the BiVO₄ surface during the crystal face reconstruction process with more favorable surface water adsorption and increased injection efficiency of photogenerated carriers. Therefore, the charge-transfer resistance (R_ct) between BVO pristine and electrolyte under AM 1.5G illumination substantially reduced from the original 15 200 to 2820 Ω after the activation. Moreover, the photocurrent density of activated BVO pristines increases more than 12 times, relative to the original BiVO₄. In this work, a new horizon for in situ photoelectric activation of semiconductor photoelectrodes with significantly enhanced PEC water splitting is provided.

Large voltage deficit and photoinduced halide segregation are the two primary challenges that hinder the advancement of wide-bandgap (WBG) (E_g ≥ 1.65 eV) perovskite solar cells (PSCs). Herein, a cation engineering approach to enhance the optoelectronic properties of formamidine–cesium (FA-Cs) WBG perovskites by incorporating methylamine (MA) as the third cation is presented. Three perovskite species with a bandgap of 1.68 eV, abbreviated as Cs_0.05, Cs_0.15, and Cs_0.25, are systematically studied by optimizing the MA content. The incorporation of MA is found to effectively enhance the crystallinity and improve the carrier lifetimes of the three perovskite species. Moreover, the microstrain in the FA-MA-Cs perovskite films is significantly reduced due to the buffer effect of MA between the size-mismatched FA and Cs, a benefit derived from the cascade cation design. The optimized compositions for the three species are Cs_0.05MA_0.2FA_0.75PbI_2.58Br_0.42, Cs_0.15MA_0.1FA_0.75PbI_2.68Br_0.32, and Cs_0.25MA_0.03FA_0.72PbI_2.73Br_0.27, respectively. Among these, Cs_0.25MA_0.03FA_0.72PbI_2.73Br_0.27 perovskite stands out due to its high crystallinity, low microstrain, and low trap density, giving rise to the highest efficiency of 20.64% with the lowest voltage loss. This perovskite also exhibits superior air, light, and thermal stability. These findings underscore the importance of rational cation design in achieving efficient and photostable WBG PSCs.

Carbon quantum dots (CQDs) are promising luminophores for luminescent solar concentrators (LSCs) in transparent photovoltaic greenhouse covers due to their high ultraviolet (UV)-light absorption coefficient, which is vital for plant growth. Herein, high quantum yield (75%) and large Stokes shift (0.706 eV) CQDs are synthesized by a simple, fast, cheap, and mass scalable method. A comprehensive study on the LSC engineering is carried out. Thin layers of CQDs with different concentrations of 1, 3, and 5 wt% and different number of layers (1–5) are coated on glass and poly(methyl methacrylate) (PMMA) waveguides, sized 5 × 5 × 0.6 and 15 × 15 × 0.6 cm³. The best performing single-layer LCS exhibits power conversion efficiency (PCE) and optical efficiency as high as 1.6% and 6.5%, respectively (LSC size 5 × 5 × 0.6 cm³), and 1.19% and 3.27% (LSC size of 15 × 15 × 0.6 cm³), respectively. Over 90 days, stability tests show a 2% PCE decrease. Tests on a small-scale greenhouse model demonstrate that transparent photovoltaic LSC roofs not only produce electricity but also control temperature inside the greenhouse. Hence, CQD-based LSCs synthesized by the scalable method can be used in commercialization of transparent greenhouses photovoltaic covers.

In recent years, significant attention has been paid to the research of light- and elevated-temperature-induced degradation (LeTID) in silicon solar cells due to the substantial power loss and instability it causes. It has been discovered that the presence of hydrogen is closely linked to the occurrence of LeTID. In this study, a thorough review and re-assessment of previously published results is conducted and connected with newly obtained data. The findings indicate a complex interaction between different hydrogen complexes and the LeTID defect states. The precursor of LeTID is connected to molecular hydrogen (H₂), while the LeTID degradation and regeneration are related to the binding of atomic hydrogen to the precursor and defect, respectively. A detailed description of the various reactions that occur under illumination and in the dark is provided. Additionally, explanation is given on how pre-annealing can significantly affect the kinetics of LeTID during subsequent light soaking. Furthermore, a comprehensive hydrogen model that incorporates these various reactions and demonstrates an agreement between simulation and experimental results is developed. Finally, the implications of the findings on strategies for mitigating LeTID are discussed.

Optical switching of the electrical operating point of individual crystalline silicon modules has previously been demonstrated as an elegant noncontact method for outdoor photoluminescence image acquisition in full daylight, with the important advantage that no modifications to the system wiring are required. Herein, a modified approach for photoluminescence imaging acquisition in large photovoltaic arrays, enabled by simultaneous optical switching of all modules within a series-connected string, is demonstrated. This improved method is a simpler approach and allows for significantly increased measurement throughput. Quantitative assessment of image data acquired in full daylight is possible since all modules in a string are series connected and operate at the same current. Excellent agreement is reported for voltage variations between modules that are inferred from daylight photoluminescence image data and measurements conducted under controlled laboratory conditions.

The nonradiative recombination arising from the interfaces of perovskite solar cells (PSCs) pose a hurdle, impacting both the efficiency and stability of devices. Functionalized organic molecules can passivate the perovskite surface to suppress the defects and can also fine-tune the microstructure. This in turn promotes reliability and performance enhancement in solar cells. Using a design protocol, cyanoguanidine diiodide is synthesized and employed as a surface passivator for the fabrication of PSCs, and boosted performance from 20.44% to 23.04% is achieved. This improvement stems from an improved fill factor reaching up to 80.64%, together with the open-circuit voltage (V_oc) measuring 1119 mV. The steady-state photoluminescence and microstructure of passivated perovskites display significant surface modification of the perovskite film which favorably impacts the charge carrier transfer at the interface of perovskite and Spiro-OMeTAD. Our findings suggest that improved solar cell performance is due to the synergetic effect of amino and cyano functional groups along with the iodide reservoir in the organic passivator.

Knowledge regarding the temperature dependence of the surface recombination at the interface between silicon and various dielectrics is critically important as it 1) provides fundamental information regarding the interfaces and 2) improves the modeling of solar cell performance under actual operating conditions. Herein, the temperature- and carrier-dependent surface recombination at the silicon–oxide/silicon and aluminum–oxide/silicon interfaces in the temperature range of 25−90 °C using an advanced technique is investigated. This method enables to control the surface carrier population from heavy accumulation to heavy inversion via an external bias voltage, allowing for the decoupling of the bulk and surface contributions to the effective lifetime. Thus, it offers a simple and versatile manner to separate the chemical passivation from the charge-assisted population control at the silicon/dielectric interface. A model is established to obtain the temperature dependence of the capture cross sections, a critical capability for the optimization of the dielectric layers and the investigation of the fundamental properties of the passivation under field operating conditions.