Enhancing Photovoltaic Performance of Inverted Planar Perovskite Solar Cells by Cobalt-Doped Nickel Oxide Hole Transport Layer

Abstract

Electron and hole transport layers have critical impacts on the overall performance of perovskite solar cells (PSCs). Herein, for the first time, a solution-processed cobalt (Co)-doped NiO film was fabricated as the hole transport layer in inverted planar PSCs, and the solar cells exhibit 18.6% power conversion efficiency. It has been found that an appropriate Co-doping can significantly adjust the work function and enhance electrical conductivity of the NiO film. Capacitance-voltage ( C- V) spectra and time-resolved photoluminescence spectra indicate clearly that the charge accumulation becomes more pronounced in the Co-doped NiO -based photovoltaic devices; it, as a consequence, prevents the nonradiative recombination at the interface between the Co-doped NiO and the photoactive perovskite layers. Moreover, field-dependent photoluminescence measurements indicate that Co-doped NiO -based devices can also effectively inhibit the radiative recombination process in the perovskite layer and finally facilitate the generation of photocurrent. Our work indicates that Co-doped NiO film is an excellent candidate for high-performance inverted planar PSCs.

Facile Synthesis of Highly Conductive Vanadium-Doped NiO Film for Transparent Conductive Oxide

“…Improved electrical conductivity and hole extraction can be achieved through doping [19]. Different dopants have been used to improve the conductivity of NiO, such as Cs [19], Cu [20], Nb [21], Y [22], Ag , Co [25], N [26], and K [27]. Among all these dopants, Cu is widely used for light doping in various TCO-based applications.…”

Low-temperature, high-speed reactive deposition of metal oxides for perovskite solar cells

“…We expect that selective doping of the nickel source with either cobalt, magnesium or copper may offer a route to increase the VOC of inverted PSCs by lowering the NiO valence band energy. 14,20,28,59 Our measurements suggest that devices containing a TiO2 ETM are characterised by high series resistance that limits the FF and PCE. Here such effects may either result from a lack of oxygen vacancies (required for n-type doping) as indicated by the XPS measurements, or may originate from the largely amorphous nature of the TiO2.…”

A flexible back-contact perovskite solar micro-module

“…phenyl-C 61 -butyric acid methyl ester, bathophenanthroline, bathocuproine) alongside the C 60 ETM, and can employ metal doping of nickel oxide (with cobalt, magnesium or copper) to lower the valence band energy of the resultant HTM film. [30][31][32][33] We believe that further modification to the directionally evaporated electrodes may allow us to further increase the V OC of our devices.…”