Solution-processed all-oxide nanostructures for heterojunction solar cells

Abstract

A low-cost, non-toxic, environmentally friendly, and solution-processed new oxide-based semiconducting material (Sn 1Àx Co x O 2 ) was developed as an absorption material for all oxide solar cell fabrication in this work. The newly developed n-type cobalt-doped tin oxide (n-Sn 1Àx Co x O 2 ) nanoparticles and p-type copper oxide (p-Cu 2 O) nanostructures were successfully synthesized via a lowtemperature solution process. Combined with the use of non-vacuum spray and hot-press processes, the n-Sn 1Àx Co x O 2 /p-Cu 2 O heterojunction solar cells exhibit low-cost and large-scale fabrication advantages. The highest power conversion efficiency (PCE) of 1.2% can be obtained from the solar cells with n-Sn 0.86 Co 0.14 O 2 /p-Cu 2 O, under AM 1.5 illumination, a noteworthy improvement in solutionprocessed all-oxide-based nanostructures heterojunction solar cells.Responding to the threats of global warming and climate change urges the development of environmentally friendly and low-cost solar cell technologies. 1,2 In addition, it is critical to develop earth-abundant absorption materials for solar cell applications. Currently, the mainstream PV market is dominated by crystalline silicon-based solar cells. 3 Although crystalline silicon-based solar cells provide high efficiency advantages, the cost due to vacuum process and limitation on large-scale production still make it hard to compete with the electricity cost of fossil energy. [3][4][5][6][7] Consequently, in addition to the demands of low-cost, and earth-abundant/non-toxic materials, a non-vacuum and large-scale process for solar cell fabrication is needed for sustainable power generation. 8,9 In order to provide solutions for low-cost and large-scale applications, spray and solution processes for new absorber layers were developed to replace vacuumbased technologies. [8][9][10] The non-vacuum technologies for solar cell fabrications, such as organics, dye-sensitized and oxide-based solar cells, are very attractive because of their potential applications on inexpensive oxide-based solar cells with minimal energy input. [10][11][12] Recently, Cu 2 O, SnO 2 , TiO 2 , CuO, ZnO, AZO and other oxide semiconducting materials were developed for low-cost and large-scale applications.

Functional Oxides for Photoneuromorphic Engineering: Toward a Solar Brain

“…[240] , [255] or nanostructured [256] arrangements. The window layer can be produced by a number of methods, including electrochemical deposition [257] , spray pyrolysis [258] , ion beam sputtering [240] , vaccum arc plasma evaporation [259] , atomic layer deposition [260] , pulsed layer deposition [261] or metal-organic chemical vapor deposition [262] . Planar Cu 2 O/ZnO heterojunction PCE is now approaching ~5% [261] (where Cu 2 O and…”

The impact of heterojunction formation temperature on obtainable conversion efficiency in n-ZnO/p-Cu2O solar cells

“…Up to now, there have been many reports on various Cu 2 O-based solar cells fabricated using Cu 2 O as the active layer [1][2][3][4][5][6][7][8][9][10][11][12][13][14], because the theoretical maximum energy conversion efficiency of a solar cell fabricated using Cu 2 O as the active layer is 20% [5]. However, a sufficiently high conversion efficiency has been difficult to achieve with Cu 2 O-based solar cells, because of the difficulty of forming a good p-n heterojunction based on p-type Cu 2 O as well as of obtaining an n-type semiconductor since Cu 2 O is spontaneously a p-type semiconductor [4,5,[15][16][17][18][19]]. An improvement of efficiency has been recently reported in p-n heterojunction solar cells fabricated by depositing n-type oxide semiconductor thin films on p-type polycrystalline Cu 2 O sheets that had been prepared by a thermal oxidization of copper sheets [10][11][12][13][14].…”

Low-cost photodetector architectures fabricated at room-temperature using nano-engineered silicon wafer and sol-gel TiO2 – based heterostructures

“…Nevertheless, amorphous TiO 2 can also provide a larger surface area and enhanced absorptivity, but at much lower processing costs 14 . Using nanostructured materials can significantly improve the performances of such heterojunction-based devices 15–18 . Indeed, TiO 2 nanostructuring has been previously used to boost responsivity from Si-TiO 2 photodetectors 13 .…”