Low‐Temperature Processed, Efficient, and Highly Reproducible Cesium‐Doped Triple Cation Perovskite Planar Heterojunction Solar Cells

Abstract

Highly efficient and reproducible cesium (Cs) doped triple cation (Cs, methylammonium (MA) and formamidinium (FA)) lead trihalide perovskite planar heterojunction (PHJ) solar cells are fabricated via low-temperature process with a simple architecture of ITO/SnO 2 /Perovskite/Spiro-OMeTAD/ Ag, of which the power conversion efficiency (PCE) up to 20.51% with negligible hysteresis and a steady output PCE of 20.22% can be achieved. Cs-intercalation is useful for forming high-quality Cs-doped triple cation perovskite films with larger gains and band gap as compared with perovskite films without Cs doping, leading to impressively enhanced photoluminescence lifetime and open circuit voltage (V oc ). Meanwhile, incorporating Cs þ into perovskite structure can result in lower charge-extraction time and prolonged charge-recombination lifetime, which are advantageous to improve the device performance. More importantly, Cs-doped triple cation PHJ perovskite solar cells (PSCs) exhibit better stability. They could maintain about 80% original PCE even exposed to air environments (humidity %40%) for over 500 hr without any encapsulation, while similar ones without Csdoping only maintain about 60% original PCE. The research work demonstrates that triple or multiple cation mixture is an effective strategy for structuring highly-efficient and stable PHJ-PSCs via low-temperature process, which may accelerate the commercialization of PSCs fabricated via large-scale printing techniques.

Defect‐Engineering‐Enabled High‐Efficiency All‐Inorganic Perovskite Solar Cells

“…Clearly, the CsPbI 3 :Br:InI 3 film exhibits higher absorption coefficient than the CsPbI 3 film. Figure d displays the transformed plots from the UV–vis absorption spectra . Bandgaps of CsPbI 3 , CsPbI 3 :Br, and CsPbI 3 :Br:InI 3 films are determined to be 1.73, 1.89, and 1.74 eV, respectively.…”

Application of a Tetra‐TPD‐Type Hole‐Transporting Material Fused by a Tröger's Base Core in Perovskite Solar Cells

“…The solid‐state ionization potential value ( I p ) was measured as 5.24 eV. This value suggests that V1160 is compatible with the perovskite (valence band edge—5.6–5.8 eV) energy levels, ensuring good charge extraction.…”

“…To investigate the performance of V1160 as an HTM, PSCs with the FTO/compact TiO 2 /mesoporous TiO 2 /amorphous SnO 2 /[(FAPbI 3 ) 0.87 (MAPbBr 3 ) 0.13 ] 0.92 (CsPbI 3 ) 0.08 /HTM/Au device architecture were constructed, utilizing state‐of‐the‐art “triple‐cation” perovskite composition. To fabricate the cells, V1160 was dissolved in chlorobenzene, with the addition of the dopants, and spin‐coated directly on top of the perovskite film (see Supporting Information for the detailed procedure).…”

Recent Advances of Device Components toward Efficient Flexible Perovskite Solar Cells

“…On the other hand, efforts have been made on the compositional engineering of perovskites to optimize fabrication temperature and further improve device performance . MAPbI 3 plays an important role in the development of PSCs and has accomplished a high PCE of 21.5% .…”