Boosting efficiency of hole conductor-free perovskite solar cells by incorporating p-type NiO nanoparticles into carbon electrodes

The balance between efficiency, stability and environmental impacts in perovskite solar cells: a review

“…A sol-gel-processed NiO nanocrystal (NC) layer has been used as the hole-transporter [66]; also a p-i-n structure (glass/indium tin oxide/NiO x /perovskite/ZnO/Al), in which the ZnO layer isolates the perovskite and Al layers, thus preventing degradation [80]; and a similar approach using chromium oxide on flexible substrates [81]. More recently p-type NiO nanoparticles embedded in a carbon matrix delivered PCE=13.26% and long term stability of 800 h in storage [54]. The use of ZnO enables low-cost processing routes as has already been demonstrated for polymeric solar cells with inverted architecture [133].…”

“…The concern about spiro-OMeTAD has been extended also to environmental issues, where the impact in several categories, such as Human Toxicity and Freshwater Ecotoxicity (ILCD methodology), is very large [17,157]. Strategies oriented to the replacement of spiro-OMeTAD or to HTL-free architectures for the perovskite solar cell have been developed; an example of this exploration is the substitution of spiro-OMeTAD by a carbon layer, with only a small reduction in PCE (from 13.24% to 10.29%), which enables a potentially strong reduction in economic cost, and furthermore, addition of NiO nanoparticles (1:20, NiO:C in weight) to the carbon electrode boosts efficiency to 13.26%, thus demonstrating the viability of the HTL free solar cell with stability of 800 h in storage [54]. Jeon et al achieved longer stability (up to 320 h under 1 Sun illumination) by replacing spiro-OMeTAD with N2,N2′, N7,N7′ -tetrakis(9,9-dimethyl-9H-fluoren-2-yl)-N2,N2′,N7,N7′-tetrakis(4-methoxyphenyl)-9,9′-spirobi[fluorene]-2,2′,7,7′-tetraamine (that can be summarized as DM); the problem with this approach is that DM also has a complex processing route making it difficult to achieve cost reductions and its environmental impact has not been estimated so far [100].…”

Analysing the Prospects of Perovskite Solar Cells within the Purview of Recent Scientific Advancements

“…These materials offer flexibility of printing as well as solution-based processing, paving the path to scale up production. Composites of p-type semiconductors bent with carbon materials, for example NiO in carbon matrix [180,217], P3HT and PMMA blended with SWCNTs [218] exhibited a great potential as HTMs for low cost PSCs. …”

Simultaneously Enhanced Efficiency and Stability of Perovskite Solar Cells with TiO2@CdS Core–Shell Nanorods Electron Transport Layer

“…Perovskite solar cells (PSCs) have attracted intensive attention as the most promising third‐generation photovoltaic devices, in which the photosensitive materials have perovskite structure with excellent properties such as the large carrier mobility, high absorption coefficient, long diffusion length, and low‐temperature solvent engineering . Since the first report of perovskite materials applied in solar cells in 2009, the power conversion efficiency (PCE) of PSCs had boosted up to 23.7% just over the past ten years…”