Synthesis and characterization of 15% efficient CIGSSe solar cells from nanoparticle inks

Abstract

We report a total-area power conversion efficiency of 15% for a copper indium gallium disulfoselenide (CIGSSe) solar cell fabricated from a copper indium gallium disulfide (CIGS) nanoparticle ink based process. Careful optimization of the fabrication process has resulted in a significant improvement in efficiency compared to our previously reported efficiency of 12%. This efficiency ranks among the highest reported in the literature for solution processed CIGSSe. Despite having an absorber thickness of approximately 700-800 nm, which is less than half the thickness of high efficiency devices grown by both coevaporation and solution processes in the literature, our devices show good short-circuit current (32.1 mA/cm 2 ). Surprisingly, the sintered film shows lateral composition fluctuations, which have not been reported for other high efficiency devices and may be responsible for the lower open circuit voltage (636 mV) observed here. This suggests an avenue for further improvement through optimization of the nanoparticle selenization process to better control composition in the sintered film.

Real-Space Mapping of Surface Trap States in CIGSe Nanocrystals Using 4D Electron Microscopy

“…[11][12][13][14][15] This often acts as a bottleneck in the use of these NCs for photoactive applications. Typically, multinary metal chalcogenides possess many desirable attributes, such as high absorption coefficient and high photo-stability for optoelectronic applications, [16][17][18][19][20][21] and a record power conversion efficiency of 21.7% has been obtained in the bulk form following physical deposition techniques, 22 which is close to the efficiency of polycrystalline silicon solar cells. But, when it comes to nanoscale, the presence of multiple trap states and the lack of the knowledge about their ultrafast carrier trapping dynamics limit their efficiency in device-based applications.…”

A Comparative Study of Nanoparticle‐Ink‐Based CIGSSe Thin Film Solar Cells on Different Back Contact Substrates

“…18 Recently, the nanoparticle-ink-based process proved its potential by showing a very high solar cell efficiency of 15%, based on a Mo back contact. 19 In this study, we demonstrated the effectiveness of a nanocrystal-ink-based CIGSSe solar cell on a transparent and conductive oxide (e.g., fluorine-doped SnO 2 , FTO)coated glass substrate. As a reference, the same CIGSSe absorber film was also synthesized on typical Mo-coated glass, and the morphologies, crystal structures, and compositional distributions of the CIGSSe films were investigated.…”

“…After sintering of the as‐prepared film, the nanoparticles are changed to uniform films of large grain size and high crystallinity . Recently, the nanoparticle‐ink‐based process proved its potential by showing a very high solar cell efficiency of 15%, based on a Mo back contact …”

Improved Quality Absorber Layer of I–III–VI2 Compound Semiconductors: Purification Process Revisited

“…The CIGS deposition by nonvacuum process offers potential advantages over vacuum processing, such as 1) uniform deposition over large area of the substrate; 2) high materials utilization; and 3) low‐cost process . Recently, several solution‐based approaches with precursor solutions, nanoparticle‐based inks, organometallic compounds, and metal alloys have been demonstrated for CIGS thin‐film solar cell fabrication with high conversion efficiencies of up to ≈16% . The photovoltaic efficiency gap between vacuum and nonvacuum processed CIGS films has been reduced in last few years thus showing promise for commercialization …”

“…[3,5,6] Recently, several solutionbased approaches with precursor solutions, nanoparticle-based inks, organometallic compounds, and metal alloys have been demonstrated for CIGS thin-film solar cell fabrication with high conversion efficiencies of up to %16%. [7][8][9][10] The photovoltaic efficiency gap between vacuum and nonvacuum processed CIGS films has been reduced in last few years thus showing promise for commercialization. [11][12][13][14] The tuning of the chemical composition of the CIGSe nanoparticles optimizes the conversion efficiency as the optical and electrical properties of the absorber layers strongly depend on the chemical stoichiometries of Cu-In-Ga-Se.…”