Inorganic hole conductor-based lead halide perovskite solar cells with 12.4% conversion efficiency

Abstract

Organo-lead halide perovskites have attracted much attention for solar cell applications due to their unique optical and electrical properties. With either low-temperature solution processing or vacuum evaporation, the overall conversion efficiencies of perovskite solar cells with organic hole-transporting material were quickly improved to over 15% during the last 2 years. However, the organic hole-transporting materials used are normally quite expensive due to complicated synthetic procedure or high-purity requirement. Here, we demonstrate the application of an effective and cheap inorganic p-type hole-transporting material, copper thiocyanate, on lead halide perovskite-based devices. With low-temperature solution-process deposition method, a power conversion efficiency of 12.4% was achieved under full sun illumination. This work represents a well-defined cell configuration with optimized perovskite morphology by two times of lead iodide deposition, and opens the door for integration of a class of abundant and inexpensive material for photovoltaic application.

Recent Progress on the Long‐Term Stability of Perovskite Solar Cells

“…Inorganic materials were explored to be good candidates as HTL owing to their intrinsically properties, such as NiO x ,103, 143 CuO x ,144 CuSCN,145 CuI,146 CuPc,147 etc. Compared to organic hole conductors, inorganic p‐type materials usually possess high chemical stability, hole mobility, low cost, and ease of synthesis.…”

New iridium complex as additive to the spiro-OMeTAD in perovskite solar cells with enhanced stability

“…13,14 Precisely, the use of new materials or modifications as HTM is a very large field to be explored. It has been demonstrated the effective use of solution-processable inorganic HTM as CuI 15 and CuSCN, 16,17 reporting efficiencies as high as 12.4%. 17 Nevertheless the most extended HTM employed in PSCs are organic wherein the organic synthesis of conductive polymers or new molecules used as additives has a fundamental role.…”

“…It has been demonstrated the effective use of solution-processable inorganic HTM as CuI 15 and CuSCN, 16,17 reporting efficiencies as high as 12.4%. 17 Nevertheless the most extended HTM employed in PSCs are organic wherein the organic synthesis of conductive polymers or new molecules used as additives has a fundamental role. The most commonly used HTM in PSCs is spiro-OMeTAD (2,2 ,7,7 -tetrakis(N,N -di-p-methoxyphenylamine)-9,9 -spirobifluorene).…”

“…22 thus obtaining values of 6.31 eV for the HOMO level. 17 From Fig. 1(b) it is clearly observed that the generated charges in the perovskite can be energetically injected into the HTM (holes) and to the titania compact layer (electrons).…”

CuSCN as selective contact in solution-processed small-molecule organic solar cells leads to over 7% efficient porphyrin-based device

“…Copper (I) thiocyanate (CuSCN) as HTL as reported earlier for organic solar cells 15 and hybrid perovskite solar cells. 16 CuSCN is an inorganic molecular semiconductor, highly soluble in diethylsulfide and diisopropyl sulphide can be readily processed to yield thin film with high transparency across the solar spectrum and its hole mobility can be achieved up to 0.01 -0.1 cm 2 /Vs after the mild thermal treatment (~100° C) and is compatible with a variety of organic D-A materials. In addition of desirable optical transparency, CuSCN posses a deep valence band edge ~5.30 -5.35 eV that can help to extract the hole from the active layer as well as maximize the V oc .…”