Alkyl‐Chain‐Regulated Charge Transfer in Fluorescent Inorganic CsPbBr₃ Perovskite Solar Cells

Abstract

Improved charge extraction and wide spectral absorption promote power conversion efficiency of perovskite solar cells (PSCs). The state‐of‐the‐art carbon‐based CsPbBr3 PSCs have an inferior power output capacity because of the large optical band gap of the perovskite film and the high energy barrier at perovskite/carbon interface. Herein, we use alkyl‐chain regulated quantum dots as hole‐conductors to reduce charge recombination. By precisely controlling alkyl‐chain length of ligands, a balance between the surface dipole induced charge coulomb repulsive force and quantum tunneling distance is achieved to maximize charge extraction. A fluorescent carbon electrode is used as a cathode to harvest the unabsorbed incident light and to emit fluorescent light at 516 nm for re‐absorption by the perovskite film. The optimized PSC free of encapsulation achieves a maximum power conversion efficiency up to 10.85 % with nearly unchanged photovoltaic performances under 80 %RH, 80 °C, or light irradiation in air.

An Efficient and Stable Perovskite Solar Cell with Suppressed Defects by Employing Dithizone as a Lead Indicator

“…The enhanced PL intensity means the attenuated non-radiative recombination. [27] The sample c shows the highest PL intensity, illustrating the lowest non-radiative recombination. Besides, the obvious red-shift of emission peaks also indicates the reduced non-radiative recombination.…”

Perovskite‐Based Tandem Solar Cells: Get the Most Out of the Sun

“…[71][72][73] However, besides stability, the bandgap of the material and the corresponding efficiency of PSCs are also critical for tandem applications. CsPbBr 3 has a wide bandgap of 2.25 eV [74] , and the state-of-the-art solar cell showed a relatively low power conversion efficiency (PCE) of 10.85%, [75] which is not suitable to couple with Si or CIGS in tandem devices. Further, the mixed halide CsPb(Br x I 1−x ) 3 family, when 0.2 < x <0.4, were reported to show better performance, [72] but their bandgap of ≈1.93 eV is still too large to meet the optimal bandgap values.…”

Efficient and Stable All‐Inorganic Perovskite Solar Cells

“…Excellent thermal, light, and moisture stabilities have been demonstrated for CsPbBr 3 films and CsPbBr 3 -based devices especially for allinorganic PSC based on CE. [37,[70][71][72]98,99] In the recent two years, PCEs of 10.5-11% have been achieved for CsPbBr 3 -based devices even based on CE. [37,[70][71][72] It is worth noting that a PCE as high as 10.85% was realized for all-inorganic CsPbBr 3 -based devices Reproduced with permission.…”

“…using inorganic materials as HTMs, [71] and a PCE up to 10.91% was demonstrated for CsPbBr 3 -based devices based on organic Spiro-OMeTAD HTM. [72] Although the very impressive stability has been testified for CsPbBr 3 -based devices, its low PCE still hinders its further commercial application, mainly originating from insufficient light harvesting due to the wide bandgap of up to 2.3 eV and serious back contact interfacial recombination losses as well as a large energy barrier.…”