Current Status of Bottom-Up Fabrication Approaches for Cu(In,Ga)Se2 Micro-Concentrator Solar Cells

in 17TH INTERNATIONAL CONFERENCE ON CONCENTRATOR PHOTOVOLTAIC SYSTEMS (CPV-17) (2022, September 02)

Cu(In,Ga)Se2 solar cells have reached a record efficiency of 23.35% and are established as a renewable energy technology. However, future large-scale fabrication might be hindered by the availability and ... [more ▼]

Cu(In,Ga)Se2 solar cells have reached a record efficiency of 23.35% and are established as a renewable energy technology. However, future large-scale fabrication might be hindered by the availability and high cost of raw materials. To reduce the amount of solar cell material, strong efforts have been devoted to the development of the micro-concentrator photovoltaics concept for Cu(In,Ga)Se2 thin film solar cells, which combines the well established concentrator photovoltaics (CPV) technology with the miniaturization of the solar cells. In this work, we review different bottom-up approaches for the fabrication of Cu(In,Ga)Se2 micro solar cells, that potentially allow the reduction of raw material, and we present the latest results on a magnetron sputtering based method for Cu(In,Ga)Se2 micro solar cells. [less ▲]

Co-evaporation of CH3NH3PbI3: How Growth Conditions Impact Phase Purity, Photostriction, and Intrinsic Stability

in ACS Applied Materials and Interfaces (2021), 13(2), 26422653

Hybrid organic–inorganic perovskites are highly promising candidates for the upcoming generation of single- and multijunction solar cells. Despite their extraordinarily good semiconducting properties ... [more ▼]

Hybrid organic–inorganic perovskites are highly promising candidates for the upcoming generation of single- and multijunction solar cells. Despite their extraordinarily good semiconducting properties, there is a need to increase the intrinsic material stability against heat, moisture, and light exposure. Understanding how variations in synthesis affect the bulk and surface stability is therefore of paramount importance to achieve a rapid commercialization on large scales. In this work, we show for the case of methylammonium lead iodide that a thorough control of the methylammonium iodide (MAI) partial pressure during co-evaporation is essential to limit photostriction and reach phase purity, which dictate the absorber stability. Kelvin probe force microscopy measurements in ultrahigh vacuum corroborate that off-stoichiometric absorbers prepared with an excess of MAI partial pressure exhibit traces of low-dimensional (two-dimensional, 2D) perovskites and stacking faults that have adverse effects on the intrinsic material stability. Under optimized growth conditions, time-resolved photoluminescence and work functions mapping corroborate that the perovskite films are less prone to heat and light degradation. [less ▲]