Enhanced Electronic Properties of SnO₂ via Electron Transfer from Graphene Quantum Dots for Efficient Perovskite Solar Cells

Abstract

Tin dioxide (SnO) has been demonstrated as an effective electron-transporting layer (ETL) for attaining high-performance perovskite solar cells (PSCs). However, the numerous trap states in low-temperature solution processed SnO will reduce the PSCs performance and result in serious hysteresis. Here, we report a strategy to improve the electronic properties in SnO through a facile treatment of the films with adding a small amount of graphene quantum dots (GQDs). We demonstrate that the photogenerated electrons in GQDs can transfer to the conduction band of SnO. The transferred electrons from the GQDs will effectively fill the electron traps as well as improve the conductivity of SnO, which is beneficial for improving the electron extraction efficiency and reducing the recombination at the ETLs/perovskite interface. The device fabricated with SnO:GQDs could reach an average power conversion efficiency (PCE) of 19.2 ± 1.0% and a highest steady-state PCE of 20.23% with very little hysteresis. Our study provides an effective way to enhance the performance of perovskite solar cells through improving the electronic properties of SnO.

Graphene Quantum‐Dot‐Modified Hexagonal Tubular Carbon Nitride for Visible‐Light Photocatalytic Hydrogen Evolution

“…[30] Furthermore, the TEM images in Figure 2d,e exactly show the uniform distribution of GQDs on the surfaceo fP -TCN withouta ny obvious aggregation. [32][33][34] Many TEM images of the GQDs also further confirm this (SupportingI nformation, Figure S3). [31] In the inset of Figure2e, we observet hat the GQDs have narrow particle size range from 2nmt o7nm, andt he average diameter is about 4.5 nm.…”

Chlorine‐modified SnO2 electron transport layer for high‐efficiency perovskite solar cells

“…A PCE as high as 20.31% was obtained with negligible hysteresis using GQD:SnO 2 as the ETL. The device performance improvement was attributed to high conductivity, high electron mobility, and low trap‐state density of the GQD:SnO 2 ETL compared to those of the SnO 2 ETL . Recently, Wang et al adopted naphthalene diimide graphene‐modified SnO 2 film as an ETL in PSCs, and a high PCE of 20.2% was achieved with a fill factor (FF) as high as 82%, which could be ascribed to enhanced electron extraction for suppressed charge accumulation at the ETL/perovskite interface, along with the increased surface hydrophobicity and interaction between the surfactant and perovskite .…”

Approaching Perfect Light Incoupling in Perovskite and Silicon Thin Film Solar Cells by Moth Eye Surface Textures

“…So far, perovskite/crystalline silicon tandem solar cells in two-terminal and four-terminal configurations have reached energy conversion efficiencies of 23.6% and 26.4%, respectively. [16][17][18][19][20][21][22][23] Much less effort has been devoted to the optimization of the optical properties of perovskite solar cells. [12,13] Amorphous silicon material with a bandgap of 1.7 eV exhibits an almost perfect bandgap for the realization of highly efficient tandem solar cells.…”