Increased efficiency of small molecule photovoltaic cells by insertion of a MoO₃hole-extracting layer

Abstract

We report a $60% increase in open circuit voltage (V oc ) and power conversion efficiency in a chloroaluminium phthalocyanine (ClAlPc)/fullerene (C 60 ) planar heterojunction photovoltaic device after insertion of a MoO 3 hole-extracting layer at the interface between the indium tin oxide (ITO) electrode and the ClAlPc donor layer, with an associated improvement in device stability. A similar improvement was observed in heterojunction devices based on mixed ClAlPc/C 60 layers. We propose that the improvements in device performance are due to the pinning of the ITO Fermi level to the valance band of the MoO 3 interlayer, where the latter is closely aligned with the highest occupied molecular orbital of ClAlPc.

Solution processed double-decked V2Ox/PEDOT:PSS film serves as the hole transport layer of an inverted planar perovskite solar cell with high performance

“…Some researches have been conducted to use inorganic transition metal oxides including nickel oxide (NiO x ), [26][27][28][29] lead sulde (PbS), 30 and molybdenum oxide (MoO x ) [31][32][33] as the HTL lm. The conduction levels of the oxides are much higher than the lowest occupied molecular orbital (LOMO) of the organic layers, which can prevent electrons from transporting in the wrong directions and improve the photo current of PSCs.…”

Interface modification of organic photovoltaics by combining molybdenum oxide (MoOx) and molecular template layer

“…It has the advantage of easily controlled deposition by thermal evaporation or solution process with little variation in properties, as well as matching with potential large-area printing or coating fabrication for OPV modules. As an efficient HTL in OPVs, MoO x can normally improve the V oc , such as in poly(3-hexyl thiophene) (P3HT)/fullerene bulk heterojunction OPVs [15] and phthalocyanine/fullerene planar heterojuncton OPVs [17][18][19]. Especially, MoO x can dramatically improve the stability of OPVs as compared with the devices without MoO x layer [19][20][21].…”

“…Molybdenum oxide (MoO x ) is one of the efficient HTL materials for both polymer and small molecular OPVs [15][16][17][18][19][20][21]. It has the advantage of easily controlled deposition by thermal evaporation or solution process with little variation in properties, as well as matching with potential large-area printing or coating fabrication for OPV modules.…”

An External Quantum Efficiency Technique to Directly Observe Current Balancing in Tandem Organic Photovoltaics

“…A great deal of progress has been made in recent years in single junction OPVs based on solution processed polymers [2][3][4][5] and vacuum deposited small molecules. [6][7][8] Promising organic tandem cells have also been demonstrated using both small molecules [9][10][11][12] and polymers. [13][14][15][16] In common with inorganic solar cells, organic tandem cells are designed so that the absorption of the active materials is complementary between the two sub-cells.…”