8.01% CuInGaSe2 solar cells fabricated by air-stable low-cost inks.

CuInGaSe(2) (CIGS), a promising thin film solar cell material, has gained lots of attention in decades due to its high energy conversion efficiency and potential lower manufacture cost over conventional Si solar cells. As a cheaper processing method compared to vacuum-based techniques, solution-based deposition has been successfully applied to fabricate electronic devices, such as transistors and solar cells. In this paper, we reported CIGS thin film solar cells with an energy conversion efficiency reaching up to 8.01% using air-stable, low-cost inks. The newly developed inks consist of commercially available, low-cost compounds and solvents and can be processed using a variety of printing and coating techniques. More importantly, the inks can produce CIGS films free of copper selenides and amorphous carbon, two common by-products from solution-based CIGS processes. The mechanism for the transformation from metal salt precursor films to CIGS absorber thin films and the influence of selenium vapour pressure on absorber film quality and photovoltaic device performance were investigated and discussed. High-quality CIGS films with micrometer-sized crystals were obtained by using higher selenization partial pressure.

Low-temperature, high-performance, solution-processed indium oxide thin-film transistors.

Solution-processed In(2)O(3) thin-film transistors (TFTs) were fabricated by a spin-coating process using a metal halide precursor, InCl(3), dissolved in acetonitrile. A thin and uniform film can be controlled and formed by adding ethylene glycol. The synthesized In(2)O(3) thin films were annealed at various temperatures ranging from 200 to 600 °C in air or in an O(2)/O(3) atmospheric environment. The TFTs annealed at 500 °C under air exhibited a high field-effect mobility of 55.26 cm(2) V(-1) s(-1) and an I(on)/I(off) current ratio of 10(7). In(2)O(3) TFTs annealed under an O(2)/O(3) atmosphere at temperatures from 200 to 300 °C exhibited excellent n-type transistor behaviors with field-effect mobilities of 0.85-22.14 cm(2) V(-1) s(-1) and I(on)/I(off) ratios of 10(5)-10(6). The annealing atmosphere of O(2)/O(3) elevates solution-processed In(2)O(3) TFTs to higher performance at lower processing temperature.