Donor–Acceptor–Donor Type Cyclopenta[2,1-b;3,4-b′]dithiophene Derivatives as a New Class of Hole Transporting Materials for Highly Efficient and Stable Perovskite Solar Cells

Three new donor–acceptor–donor type (D–A–D) hole-transporting materials (HTMs), YC-1–YC-3, based on the 4-dicyanomethylene-4H-cyclopenta­[2,1-b;3,4-b′]­dithiophene (DiCN-CPDT) core structure endowed with two arylamino-based units as peripheral groups were designed, synthesized, and applied in perovskite solar cells (PSCs). Hole mobility, steady-state photoluminescence, thin-film surface morphology on top of the perovskite layer, and photovoltaic performance for the YC series were systematically investigated and compared with those of Spiro-OMeTAD. It was found that YC-1 exhibited more efficient hole transport and extraction characteristics at the perovskite/HTM interface. Meanwhile, the film of YC-1 showed a homogeneous and dense capping layer coverage on the perovskite layer without any pinholes, leading to the improvement of the fill factor and open circuit voltage. The PSC device based on YC-1 as a HTM exhibited a high power conversion efficiency (PCE) of 18.03%, which is comparable to that of the device based on the benchmark Spiro-OMeTAD (18.14%), and also a better long-term stability with 85% of the initial efficiency retained in excess of 500 h under the condition of 30% relative humidity, presumably due to the hydrophobic nature of the material. This work demonstrates that the dicyanomethylene-CPDT-based derivatives are promising HTMs for efficient and stable PSCs

Universal Surface Passivation of Organic–Inorganic Halide Perovskite Films by Tetraoctylammonium Chloride for High-Performance and Stable Perovskite Solar Cells

The power conversion efficiency (PCE) of perovskite solar cells has been showing rapid improvement in the last decade. However, still, there is an unarguable performance deficit compared with the Schockley–Queisser (SQ) limit. One of the major causes for such performance discrepancy is surface and grain boundary defects. They are a source of nonradiative recombination in the devices that not only causes performance loss but also instability of the solar cells. In this study, we employed a direct postsurface passivation strategy at mild temperatures to modify perovskite layer defects using tetraoctylammonium chloride (TOAC). The passivated perovskite layers have demonstrated extraordinary improvement in photoluminescence and charge carrier lifetimes compared to their control counterparts in both Cs0.05(FAPbI3)0.83(MAPbBr3)0.17 and MAPbI3-type perovskite layers. The investigation on electron-only and hole-only devices after TOAC treatment revealed suppressed electron and hole trap density of states. The electrochemical study demonstrated that TOAC treatment improved the charge recombination resistance of the perovskite layers and reduced the charge accumulation on the surface of perovskite films. As a result, perovskite solar cells prepared by TOAC treatment showed a champion PCE of 21.24% for the Cs0.05(FAPbI3)0.83(MAPbBr3)0.17-based device compared to 19.58% without passivation. Likewise, the PCE of MAPbI3 improved from 18.09 to 19.27% with TOAC treatment. The long-term stability of TOAC-passivated perovskite Cs0.05(FAPbI3)0.83(MAPbBr3)0.17 devices has retained over 97% of its initial performance after 720 h in air

Efficient and Stable Self-Passivation Perovskite Solar Cells Prepared in Ambient Air Based on an Antisolvent-Free Method

Solution processable perovskite solar cells (PSCs) are one of the most promising candidates for commercialization. However, the perovskite film preparation method is limited by the mandatory antisolvent process under an inert gas atmosphere which significantly influenced its mass production. In this study, we developed a perovskite film preparation without the requirement of antisolvent dripping in air. We employed various solvents to prepare perovskite films and studied their influence on perovskite nucleation and morphology for the respective solvents. Among them, the perovskite prepared using dimethylacetamide (DMAc), which has low solubility and high interaction with PbI2, demonstrated a highly crystalline perovskite black phase without antisolvent dripping. Furthermore, we found that the perovskite concentration played an important role in the perovskite film quality, where the high concentration DMAc-based perovskite produced a smooth and dense perovskite film by the antisolvent-free method in air. PSCs fabricated using this technique delivered a champion power conversion efficiency (PCE) of 20.1%. At the same time, the best device prepared by the blade-coated method also got 18% PCE. Moreover, the unencapsulated devices exhibited excellent stability, which retained more than 90% of their initial efficiency after 47 days in air. This work provides a facile and cost-effective method toward a controllable fabrication of high-performance antisolvent-free MAPbI3-based solar cells

Efficient and Stable Self-Passivation Perovskite Solar Cells Prepared in Ambient Air Based on an Antisolvent-Free Method

Solution processable perovskite solar cells (PSCs) are one of the most promising candidates for commercialization. However, the perovskite film preparation method is limited by the mandatory antisolvent process under an inert gas atmosphere which significantly influenced its mass production. In this study, we developed a perovskite film preparation without the requirement of antisolvent dripping in air. We employed various solvents to prepare perovskite films and studied their influence on perovskite nucleation and morphology for the respective solvents. Among them, the perovskite prepared using dimethylacetamide (DMAc), which has low solubility and high interaction with PbI2, demonstrated a highly crystalline perovskite black phase without antisolvent dripping. Furthermore, we found that the perovskite concentration played an important role in the perovskite film quality, where the high concentration DMAc-based perovskite produced a smooth and dense perovskite film by the antisolvent-free method in air. PSCs fabricated using this technique delivered a champion power conversion efficiency (PCE) of 20.1%. At the same time, the best device prepared by the blade-coated method also got 18% PCE. Moreover, the unencapsulated devices exhibited excellent stability, which retained more than 90% of their initial efficiency after 47 days in air. This work provides a facile and cost-effective method toward a controllable fabrication of high-performance antisolvent-free MAPbI3-based solar cells

Efficient and Stable Self-Passivation Perovskite Solar Cells Prepared in Ambient Air Based on an Antisolvent-Free Method

Solution processable perovskite solar cells (PSCs) are one of the most promising candidates for commercialization. However, the perovskite film preparation method is limited by the mandatory antisolvent process under an inert gas atmosphere which significantly influenced its mass production. In this study, we developed a perovskite film preparation without the requirement of antisolvent dripping in air. We employed various solvents to prepare perovskite films and studied their influence on perovskite nucleation and morphology for the respective solvents. Among them, the perovskite prepared using dimethylacetamide (DMAc), which has low solubility and high interaction with PbI2, demonstrated a highly crystalline perovskite black phase without antisolvent dripping. Furthermore, we found that the perovskite concentration played an important role in the perovskite film quality, where the high concentration DMAc-based perovskite produced a smooth and dense perovskite film by the antisolvent-free method in air. PSCs fabricated using this technique delivered a champion power conversion efficiency (PCE) of 20.1%. At the same time, the best device prepared by the blade-coated method also got 18% PCE. Moreover, the unencapsulated devices exhibited excellent stability, which retained more than 90% of their initial efficiency after 47 days in air. This work provides a facile and cost-effective method toward a controllable fabrication of high-performance antisolvent-free MAPbI3-based solar cells

Efficient and Stable Self-Passivation Perovskite Solar Cells Prepared in Ambient Air Based on an Antisolvent-Free Method

Solution processable perovskite solar cells (PSCs) are one of the most promising candidates for commercialization. However, the perovskite film preparation method is limited by the mandatory antisolvent process under an inert gas atmosphere which significantly influenced its mass production. In this study, we developed a perovskite film preparation without the requirement of antisolvent dripping in air. We employed various solvents to prepare perovskite films and studied their influence on perovskite nucleation and morphology for the respective solvents. Among them, the perovskite prepared using dimethylacetamide (DMAc), which has low solubility and high interaction with PbI2, demonstrated a highly crystalline perovskite black phase without antisolvent dripping. Furthermore, we found that the perovskite concentration played an important role in the perovskite film quality, where the high concentration DMAc-based perovskite produced a smooth and dense perovskite film by the antisolvent-free method in air. PSCs fabricated using this technique delivered a champion power conversion efficiency (PCE) of 20.1%. At the same time, the best device prepared by the blade-coated method also got 18% PCE. Moreover, the unencapsulated devices exhibited excellent stability, which retained more than 90% of their initial efficiency after 47 days in air. This work provides a facile and cost-effective method toward a controllable fabrication of high-performance antisolvent-free MAPbI3-based solar cells

Efficient and Stable Self-Passivation Perovskite Solar Cells Prepared in Ambient Air Based on an Antisolvent-Free Method

Solution processable perovskite solar cells (PSCs) are one of the most promising candidates for commercialization. However, the perovskite film preparation method is limited by the mandatory antisolvent process under an inert gas atmosphere which significantly influenced its mass production. In this study, we developed a perovskite film preparation without the requirement of antisolvent dripping in air. We employed various solvents to prepare perovskite films and studied their influence on perovskite nucleation and morphology for the respective solvents. Among them, the perovskite prepared using dimethylacetamide (DMAc), which has low solubility and high interaction with PbI2, demonstrated a highly crystalline perovskite black phase without antisolvent dripping. Furthermore, we found that the perovskite concentration played an important role in the perovskite film quality, where the high concentration DMAc-based perovskite produced a smooth and dense perovskite film by the antisolvent-free method in air. PSCs fabricated using this technique delivered a champion power conversion efficiency (PCE) of 20.1%. At the same time, the best device prepared by the blade-coated method also got 18% PCE. Moreover, the unencapsulated devices exhibited excellent stability, which retained more than 90% of their initial efficiency after 47 days in air. This work provides a facile and cost-effective method toward a controllable fabrication of high-performance antisolvent-free MAPbI3-based solar cells

Efficient and Stable Self-Passivation Perovskite Solar Cells Prepared in Ambient Air Based on an Antisolvent-Free Method

Solution processable perovskite solar cells (PSCs) are one of the most promising candidates for commercialization. However, the perovskite film preparation method is limited by the mandatory antisolvent process under an inert gas atmosphere which significantly influenced its mass production. In this study, we developed a perovskite film preparation without the requirement of antisolvent dripping in air. We employed various solvents to prepare perovskite films and studied their influence on perovskite nucleation and morphology for the respective solvents. Among them, the perovskite prepared using dimethylacetamide (DMAc), which has low solubility and high interaction with PbI2, demonstrated a highly crystalline perovskite black phase without antisolvent dripping. Furthermore, we found that the perovskite concentration played an important role in the perovskite film quality, where the high concentration DMAc-based perovskite produced a smooth and dense perovskite film by the antisolvent-free method in air. PSCs fabricated using this technique delivered a champion power conversion efficiency (PCE) of 20.1%. At the same time, the best device prepared by the blade-coated method also got 18% PCE. Moreover, the unencapsulated devices exhibited excellent stability, which retained more than 90% of their initial efficiency after 47 days in air. This work provides a facile and cost-effective method toward a controllable fabrication of high-performance antisolvent-free MAPbI3-based solar cells