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

Abstract

A high‐quality electron transport layer (ETL) is a critical component for the realization of high‐efficiency perovskite solar cells. We developed a controllable direct‐contact reaction process to prepare a chlorinated SnO2 (SnO2‐Cl) ETL. It is unique in that (a) 1′2‐dichlorobenzene is used to provide more reactive Cl radicals for more in‐depth passivation; (b) it does not introduce any impurities other than chlorine. It is found that the chlorine modification significantly improves the electron extraction. Consequently, its associated solar cell efficiency is increased from 17.01% to 17.81% comparing to the pristine SnO2 ETL without the modification. The hysteresis index is significantly reduced to 0.017 for the SnO2‐Cl ETL.

40.1% Record Low‐Light Solar‐Cell Efficiency by Holistic Trap‐Passivation using Micrometer‐Thick Perovskite Film

“…The trap density can be calculated from N traps = 2 εε 0 V TFL / eL 2 equation. [ 20,22 ] The trap density of the control device is 4.56 × 10 15 cm −3 for electron defects, and 5.31 × 10 15 cm −3 for hole defects, which are significantly reduced to 2.69 × 10 15 and 3.14 × 10 15 cm −3 through holistic passivation, demonstrating that the trap density of perovskite film can be effectively reduced by the holistic passivation, which supports our previous discussion that the prolonged charge carrier lifetime with holistic passivation is due to the reduction of defect density in the perovskite film.…”

“…Recently, PSCs were also found to hold promise in low‐light environments, [ 10–26 ] such as indoors, cloudy conditions, early morning, late evening, etc. PSCs have a strong light response in the range of 300–850 nm, [ 27,28 ] which completely covers the emission range of commonly used indoor light sources.…”

Up-Scalable Fabrication of SnO2 with Multifunctional Interface for High Performance Perovskite Solar Modules

“…The two spin–orbit splitting peaks of Sn 3d in the SnO 2 -ETL in Fig. 2 c shift from 495.1 and 486.8 eV to high binding energies of 495.5 and 487.1 eV (SnO 2 /K-ETL), which indicates more Sn (II) conversion to Sn (IV) [ 46 , 47 ]. In parallel, the Cl ions are inevitably adsorbed on the top of SnO 2 film because of the precursor solution containing SnCl 2 and HCl.…”

In Situ-Formed and Low-Temperature-Deposited Nb:TiO2 Compact-Mesoporous Layer for Hysteresis-Less Perovskite Solar Cells with High Performance

“…Compared with the mesoporous-type PSCs, planar-type PSCs can be fabricated using a low-temperature and low-cost process [22]. However, planar-type PSCs usually suffer from poor electron conductivity, severe charge recombination, and relatively lower crystallinity, resulting in low PCE with severe hysteresis behavior [23,24].…”