Centimetre-scale perovskite solar cells with fill factors of more than 86 per cent

Abstract

Rapid development of both efficiency 1 and stability 2 mean that perovskite solar cells are at the forefront of emerging photovoltaic technologies. State-of-the-art cells exhibit voltage losses 3-8 approaching the theoretical minimum and near-unity internal quantum efficiency 9-13 , but conversion efficiencies are limited by the fill-factor (FF < 83%, below the Shockley-Queisser limit of ~90%). This limitation results from non-ideal charge transport between the perovskite absorber and the cell's electrodes 5,8,13-16 . Reducing the electrical series resistance of charge transport layers is therefore crucial for improving efficiency. Here we introduce a reverse-doping process to fabricate nitrogen-doped titanium oxide electron transport layers with outstanding charge transport performance. By incorporating this charge transport material into perovskite solar cells, we demonstrate 1cm 2 cells with FFs >86%, and an average FF ~ 85.3%. We also report a certified steady-state efficiency record of 22.6% for a 1cm 2 cell (23.33% ± 0.58% from reverse current-voltage scan).Nitrogen-doped titanium oxide (titanium oxynitride, TiO x N y ) has been widely investigated for photocatalysis 17,18 , but rarely in perovskite solar cells (PSCs). PSCs incorporating solution-processed TiO x N y have been reported, but device performances have

Buried Interface Modification in Perovskite Solar Cells: A Materials Perspective

“…Metal halide perovskite with excellent photophysical properties has made great achievements in the field of optoelectronics, such as photovoltaic (PV), light-emitting diode (LED), photodetector, laser, etc. [1][2][3][4][5][6][7][8][9][10][11] Among these, the state-of-the-art perovskite solar cells (PSCs) with unprecedented certified record efficiency of 25.7% have made great progress (Figure 1a), [12][13][14][15][16][17][18][19][20][21][22][23][24] which is comparable to current industrial-grade mono-crystalline silicon solar cells. [24] This fantastic efficiency together with low-cost and flexible fabrication makes PSCs more attractive than the other efficient photovoltaic technologies.…”

Geometric Optimization of Perovskite Solar Cells with Metal Oxide Charge Transport Layers

“…It is highest value of fill factor. However, in practice [ 50 ], the maximum value of the fill factor depends mainly on the series resistance, shunt resistance, and recombination rate. For an ideal solar cell, that has an ideality coefficient ( n = 1), can be expressed in the below equation [ 51 ]: with: V oc is the open-circuit voltage, and FF is the fill factor.…”

Toward Efficient Perovskite Solar Cells: Progress, Strategies, and Perspectives

“…This strategy produced high-quality TiO x N y films by oxidizing sputtered titanium nitride thin films, greatly improving the film conductivity under a controlled annealing temperature and resulting in a record value of FF and impressive device performance. 45 The results prove that the doping strategy can be an important pathway for the development of future high-efficiency PSCs. Additionally, surface treatment of oxide NPs further can improve the oxide film's electrical properties and minimize its surface defects.…”

“…Recently, to improve film conductivity, a reverse-doping method was reported. This strategy produced high-quality TiO x N y films by oxidizing sputtered titanium nitride thin films, greatly improving the film conductivity under a controlled annealing temperature and resulting in a record value of FF and impressive device performance . The results prove that the doping strategy can be an important pathway for the development of future high-efficiency PSCs.…”