Diluted-CdS Quantum Dot-Assisted SnO₂ Electron Transport Layer with Excellent Conductivity and Suitable Band Alignment for High-Performance Planar Perovskite Solar Cells

Abstract

An electron transport layer (ETL) with excellent conductivity and suitable band alignment plays a key role in accelerating charge extraction and transfer for achieving highly efficient planar perovskite solar cells (PSCs). Herein, a novel diluted-cadmium sulfide quantum dot (CdS QD)-assisted SnO2 ETL has been developed with a low-temperature fabrication process. The slight addition of CdS QDs first enhances the crystallinity and flatness of SnO2 ETLs so that it provides a promising workstation to obtain high-quality perovskite absorption layers. It also amazingly increases the conductivity of the SnO2 ETL by an order of magnitude and regulates the energy level matching between the SnO2 ETL and perovskite. These outstanding properties greatly accelerate the charge extraction and transfer. Thus, the MAPbI3-based PSCs with such a diluted-CdSQD-assisted SnO2 ETL achieve a maximum power conversion efficiency of 20.78% and obtain a better stability of devices in air. These findings testify the importance and potential of semiconductor QD modification on ETLs, which may pave the way for developing such composite ETLs for further enhancing photovoltaic performance of planar PSCs.

Efficient and Stable Carbon‐Based CsPbIBr2 Perovskite Solar Cells by 4‐Aminomethyltetrahydropyran Acetate Modification

“…and vacuum permittivity, respectively. [ 38–39 ] The V TFL and N t of the 4‐AMTHP‐Ac‐modified CsPbIBr 2 PSC is 1.194 V and 3.10 × 10 16 cm −3 , respectively, lower than those of the pristine one (1.402 V and 3.64 × 10 16 cm −3 , respectively), indicating that the trap state of the 4‐AMTHP‐Ac modified CsPbIBr 2 film is significantly reduced.…”

Strategies for high‐performance perovskite solar cells from materials, film engineering to carrier dynamics and photon management

“…In the monolayer of SnO 2 , additive is employed to achieve this aim. Same as the TiO 2 , the additive using in SnO 2 includes metal ion (e.g., Li + , 422 Mg 2+ , 423,424 Eu 3+ , 397 Y 3+ , 425 Zr 4+ , 426 Nb 5+ 427,428 ), function material (e.g., TiCl 4 , 429 KCl, 430 RbF, 393 Eu‐WO x , 431 MXene, 394,432,433 NH 4 F, 403 CdS, 434 phosphoric acid, 435 , 435 g‐C 3 N 4 , 436 EDTA, 437 ionic liquid, 406 SPF, 438 PEG, 439 graphene, 440 carbon, 441,442 fullerene and its derivatives, 443–446 ) and plasma gas (e.g., N 2 , 447 Ar and O 2 448 ). For example, Park et al 422 demonstrated that Li + can enhance the conductivity and induce a downward shift of HOMO and LUMO of SnO 2 , which facilitated injection and transfer of electrons from t MAPbI 3 perovskite to SnO 2 .…”

Selection, Preparation and Application of Quantum Dots in Perovskite Solar Cells

“…In 2021, Lv et al [ 49 ] reported the modification of SnO 2 using dilute CdS QDs. The crystallinity and flatness of SnO 2 were enhanced by the modification of CdS QDs.…”