Abstract
Considering the increasing global demand for energy and the harmful ecological impact of conventional energy sources, it is obvious that development of clean and renewable energy is a necessity. Since the Sun is our only external energy source, harnessing its energy, which is clean, non-hazardous and infinite, satisfies the main objectives of all alternative energy strategies. With attractive features, i.e., good performance, low-cost potential, simple processibility, a wide range of applications from portable power generation to power-windows, photoelectrochemical solar cells like dye-sensitized solar cells (DSCs) represent one of the promising methods for future large-scale power production directly from sunlight. While the sensitization of n-type semiconductors (n-SC) has been intensively studied, the use of p-type semiconductor (p-SC), e.g., the sensitization of wide bandgap p-SC and hole transport materials with p-SC have also been attracting great attention. Recently, it has been proved that the p-type inorganic semiconductor as a charge selective material or a charge transport material in organometallic lead halide perovskite solar cells (PSCs) shows a significant impact on solar cell performance. Therefore the study of p-type semiconductors is important to rationally design efficient DSCs and PSCs. In this review, recent published works on p-type DSCs and PSCs incorporated with an inorganic p-type semiconductor and our perspectives on this topic are discussed.
Highlights
Since the seminal paper of O’Regan and Grätzel in 1991 [1] dye-sensitized solar cells (DSCs) have become attractive for harvesting solar energy [2,3,4,5,6]
The typical DSC architecture based on a redox electrolyte is broadly composed five components: (1) a mechanical support coated with a transparent conductive oxide (TCO); (2) the semiconductor film, usually TiO2 ; (3) a sensitizer (S) adsorbed on the surface of the semiconductor; (4) an electrolyte containing a redox mediator (M/M ); (5) a counter electrode capable of regenerating the redox mediator
Zhang et al demonstrated a solid state p-type DSC in which NiO is employed as a p-type semiconductor (p-SC), and the triphenylamine (TPA) based organic dye P1 as a sensitizer, and a solid electron transport material (ETM), phenyl-C61-butyric acid methyl ester (PCBM), is employed to replace liquid redox couple electrolyte [79]
Summary
Since the seminal paper of O’Regan and Grätzel in 1991 [1] dye-sensitized solar cells (DSCs) have become attractive for harvesting solar energy [2,3,4,5,6]. The use of inorganic charge transport layer of electron transport material (ETM) and HTM for PSCs has recently been demonstrated to protect the perovskite photoactive layer from exposure to ambient environments, enhancing the resistance to degradation of perovskite and achieving highly stable perovskite-based solar cells [33,34,35,36] The scope of this perspective review is to present the recent developments in DSCs and PSCs based on inorganic p-type semiconductors, including NiO, CuSCN, CuI, Cu2 O and CuO. It was found that the triethylamine-coordinated Cu(II) led to hole conductivity from 0.01 to 1.42 S/m and its application into SSDSC achieved a PCE of 3.4% [53] Another p-type wide-bandgap (~3.1 eV) semiconductor, copper iodide (CuI), is an ionic solid and serves as a potential candidate of HTM on the basis of its suitable valance band (VB) position, good optical transparency, higher hole mobility (0.5–2 cm2 /(Vs)) over CuSCN, and compatibility of solution-deposited process with the perovskite absorber. Further improvement achieved by interfacial engineering to improve contact between CuI and dye molecules was demonstrated: [55,61,62,63] and the best PCE of 7.4% from SSDSC employing PEDOT:PSS modified with guanidine thiocyanate was reported by Sakamoto et al in 2012 [64]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
