Perovskite Solar Cells Based on Nanocrystalline SnO2 Material with Extremely Small Particle Sizes

Abstract

In this work, we report the synthesis of SnO 2 nanocrystalline material and its application in perovskite solar cells. The material has been characterised comprehensively by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, selected area diffraction, and N 2 adsorption analysis. The results have revealed that the average particle size of the SnO 2 material was less than 3 nm, resulting in a large specific surface area of 173.9 m 2 g À1 . The investigation of the material in perovskite solar cells as electron-transport layer showed that pure SnO 2 material did not favour the photovoltaic performance of the device. The best solar cell obtained with one layer of SnO 2 film (22 nm) showed an energy conversion efficiency of 2.19 % under an illumination intensity of 100 mW cm À2 . Beyond this thickness, the performance of the solar cells decreased significantly with increasing thickness of the SnO 2 film due to a dramatic decrease in the photocurrent density. Nevertheless, it has been found that SnO 2 material containing a small amount of metal tin (1.3 %) significantly improved the performance of the solar cell to 8.7 %. The possible reason for this phenomenon has been discussed based on the consideration of the energy band alignment of materials in the perovskite solar cells.

Mesoscopic Oxide Double Layer as Electron Specific Contact for Highly Efficient and UV Stable Perovskite Photovoltaics

“…In addition, Song et al deposited a thin layer of SnO 2 on top of anodized amorphous TiO 2 (a-TiO 2 ), yielding a PCE of 21.1% . In fact, they concur that using SnO 2 as EEL the photovoltaic performance and stability are increased with decreasing the undesirable hysteresis effect. − …”

“…27 While none of these results were certified, they concur that using SnO2 as EEL the photovoltaic performance and stability are increased with decreasing the undesirable hysteresis effect. [29][30][31] Here we introduce a mesoscopic oxide double layer as an electron selective contact consisting of a scaffold of TiO2 nanoparticles coated by a thin film of amorphous SnO2 (a-SnO2) using solution deposition. The band gap of the a-SnO2 exceeds that of the crystalline tetragonal polymorph by 0.05 eV, affording perfect alignment of its conduction band with that of the perovskite light harvester.…”

Modification Engineering in SnO2 Electron Transport Layer toward Perovskite Solar Cells: Efficiency and Stability

“…In 2015, there were only ten papers about the use of SnO 2 as the ETL for PSCs. [45][46][47][48][49][50][51][52][53][54] This figure sharply increased to over 200 in 2019, along with a rising PCE exceeding 23%. [55] An efficiency map of SnO 2 based PSCs is shown in Figure 1.…”

Doping effects in SnO2 transport material for high performance planar perovskite solar cells

“…Several approaches have been made to prepare SnO 2 transport materials. In addition to the process optimization [14,[16][17][18], doping is a robust and efficient modification method to adjust the electric and optical properties of the pristine ETL in order to enhance one or several designated parameters of the resulting solar cell devices, which has also been widely demonstrated in TiO 2 [19][20][21][22]. Recently, the electron transport properties of SnO 2 have been improved by various doping elements with different valence states, namely Li + , Mg 2+ , Sb 3+ , Y 3+ and Nb 5+ [23][24][25][26][27].…”