Copper indium selenide water splitting photoanodes with artificially designed heterophasic blended structure and their high photoelectrochemical performances. (April 2018)

• Record Type: Journal Article
• Authors: Kim, Joo Sung; Baek, Seung Ki; Kim, Young Been; Do, Hyun Woo; Kwon, Yong Hun; Cho, Sung Woon; Yun, Young Dae; Yoon, Jae Hong; Lee, Han-Bo-Ram; Kim, Sang-Woo; Cho, Hyung Koun
• Is Part Of: Nano energy. Volume 46(2018)
• Page Start: 1
• Page End: 10
• Publication Date: 2018-04
• Subjects: Photoelectrochemical cell -- Heterophasic blended structure -- Photoanode -- Built-in potential -- Charge separation; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2018.01.023
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Conventional p- CuInSe2 absorbers for solar cells have been homogenously synthesized using multi-step process despite a narrow crystal phase region in the phase diagram and the existence of various secondary phases. In contrast, here we propose artificially-designed heterophasic blended copper indium selenide compounds for water splitting photoanodes using a simple one-step annealing synthetic process where the electrodeposited metal precursors were directly annealed with Se vapor injection and without additional intermediate steps. The resultant product is revealed to possess a novel " phase-blended structure " comprising two phases of p- type CuInSe2 and n- type CuIn3 Se5 crystals. The CuInSe2 nanoparticles with a higher Cu fraction are three-dimensionally (3D) embedded in the n- type CuIn3 Se5 matrix, which has been verified by various analysis methods such as X-ray diffraction, transmission electron microscopy, and capacitance-voltage curve. The average diameter of the CuInSe2 nanoparticles is 66.8 nm and the interval between the nanoparticles in the CuIn3 Se5 matrix is 67.6 nm. Consequently, the phase-blended structure photoabsorber exhibits a remarkably enhanced anodic photocurrent of 12.7 mA/cm 2 at 1.23 V versus the reversible hydrogen electrode. The considerably enhanced photocurrent gain of the phase-blended structure photoanode is attributed to the excellent charge separation facilitated by the built-in potential generated from the 3D p-n junction. Graphical abstract: We report an inorganic heterophasic blended structure with remarkably enhanced photocurrent performance via built-in potential between p -type CuInSe2 nanoparticles and n -type CuIn3 Se5 matrix.fx1 Highlights: Inorganic heterophasic blended structure was synthesized via one-step annealing process of electrodeposited Cu/In bilayers. We designed inorganic heterophasic blended structure consisting of p -type CuInSe2 nanoparticles and n -type CuIn3 Se5 matrix. The nanoscale CuInSe2 nanoparticles with a higher Cu fraction were three-dimensionally embedded in n -type CuIn3 Se5 matrix. Phase-blended structure resulted in sufficient depletion and efficiently separated photo-generated electron-hole pairs. Phase-blended structure CIS showed remarkably enhanced photocurrent and good stability with an ultra-thin Al2 O3 layer.