Self-doping synthesis of trivalent NiO as a hole transport layer for high fill factor and efficient inverted perovskite solar cells.

Nickel oxide (NiOx) as a hole transport layer has been vastly investigated in perovskite solar cells (PSCs) due to the nature of p-type doping, highly transparent materials, and deep-lying valence bands. In this paper, a new phase based on trivalent Ni2O3 is synthesized by low temperature solution processing of mixed nickel (acetate/nitrate). In comparison, high-temperature solution-processing of divalent NiOx resulted in novel Ni2O3 thin films that display better consistency and superior energy compatibility with perovskite thin films.

Efficient and Stable Planar n-i-p Perovskite Solar Cells with Negligible Hysteresis through Solution-Processed Cu O Nanocubes as a Low-Cost Hole-Transport Material.

Organic-inorganic halide perovskite solar cells (PSCs) have reached certified efficiencies of over 23 % with expensive organic hole-transporting materials. However, the use of an inorganic hole-transport layer (HTL) remains crucial as it would reduce cost combined with higher mobility and stability. In this direction, the application of Cu O as the top layer in PSCs is still complicated owing to the difficulty of solution processing.

High Open-Circuit Voltage of 1.134 V for Inverted Planar Perovskite Solar Cells with Sodium Citrate-Doped PEDOT:PSS as a Hole Transport Layer.

Poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate (PEDOT:PSS) plays an important role in inverted planar perovskite solar cells (IPPSCs) as an efficient hole extraction and transfer layer (HTL). The IPPSCs based on PEDOT:PSS normally display inferior performance with a reduced open-circuit voltage. To address this problem, here sodium citrate-doped PEDOT:PSS is adopted as an effective HTL for improving the performance of IPPSCs.

The direct observation of electron backflow in an organic heterojunction formed by two n-type materials.

Many physical processes such as exciton interfacial dissociation, exciton interfacial recombination, and exciton-electron and exciton-hole interactions coexist at the interface of organic solar cells (OSC). In this study, the direction of free charge generation is defined as the direction from the interface to the side where free charges are left. For a p-n type device, the direction of free electron (hole) generation from exciton dissociation at the donor/accepter (D/A) interface is the same as the subsequent transportation direction under the built-in electric field.

Bidirectional mediation of TiO2 nanowires field effect transistor by dipole moment from purple membrane.

Bacteriorhodopsin-embedded purple membrane (bR-PM) is one of the most promising biomaterials for various bioelectronics applications. In this work, we demonstrate that a dipole bio-originated from bR-PM can bidirectionally mediate the performance of a bottom-contact TiO(2) nanowire field effect transistor (FET) for performance improvement. When negative gate voltage is applied, both transfer and output characteristics of the TiO(2) nanowire FET are enhanced by the bR-PM modification, resulting in a hole mobility increased by a factor of 2.

Evidence of harvesting electricity by exciton recombination in an n-n type solar cell.

Free electrons and holes bounded by weak interactions in organic molecules must be generated from excitons to produce photocurrent in organic solar cells. Free charge carriers, in either small molecule- or polymer-based solar cells, are generated so far by dissociation of excitons at the donor-acceptor interface through injecting electrons (holes) from a donor (acceptor) into an acceptor (donor) while leaving holes (electrons) in the donor (acceptor). Here we report a new way, intermolecular exciton recombination, to generate free carriers from organic semiconductors.