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Life cycle metrics evolution specific to the climate zone of photovoltaic (PV) operation would give detailed insights on the environmental and economic performance. At present, vast literature is available on the PV life cycle metrics where only the output energies ignoring the degradation rate (DR) influence. In this study, the environ-economic analysis of three PV technologies, namely, multi-crystalline silicon (mc-Si), amorphous silicon (a-Si) and hetero-junction with an intrinsic thin layer (HIT) have been carried out in identical environmental conditions. The energy performance parameters and the DR rate of three PV technologies are evaluated based on the monitored real time data from the installation site in hot semi-arid climates. The assessment demonstrates that the HIT PV module technology exhibits more suitable results compared to mc-Si and a-Si PV systems in hot semi-arid climatic conditions of India. Moreover, energy metrices which includes energy payback time (EPBT), energy production factor (EPF) and life cycle conversion efficiency (LCCE) of the HIT technologies are found to be 1.0, 24.93 and 0.15 years, respectively. HIT PV system has higher potential to mitigate the CO2 and carbon credit earned compared to mc-Si and a-Si PV system under hot semi-arid climate. However, the annualized uniform cost (UAC) for mc-Si (3.60 Rs/kWh) and a-Si (3.40 Rs/kWh) are more admissible in relation to the HIT (6.63 Rs/kWh) PV module type. We conclude that the approach of considering DR influenced life cycle metrics over the traditional approach can support to identify suitable locations for specific PV technology.

Organometal halide perovskites are being extensively studied as they can serve as an excellent active medium in various optoelectronic devices such as solar cells, light-emitting diodes (LEDs), lasers, etc. We report the fabrication of highly controlled single-phase mixed halide two-dimensional (2D) perovskites by successive doping of inorganic dopant, potassium iodide (KI), in 2D perovskite 2-(1cyclohexenyl) ethylammonium lead bromide, (C 6 H 9 C 2 H 4 NH 3 ) 2 PbBr 4 (CHPB). Our computational investigations further confirm the thermodynamic stability of mixed anion lattices. A stoichiometric increase of KI in CHPB beyond critical passivation levels results in a uniform bandgap tunability of thin films from the UV (∼3.21 eV) to green (∼2.50 eV) region of spectra. Distinctly linear, tunable, and single-phase strong room-temperature exciton absorbance (∼401−508 nm) and emission peaks (∼416−518 nm) in the blue-green spectral region are observed with the increase of KI concentration levels in thin-film samples. Doped two-dimensional (2D) perovskite films exhibit a minimum stokes shift parameter of 40 meV, which is very small compared to the conventional route of mixing two perovskite precursor solutions. X-ray diffraction studies show that the layered structure of doped 2D perovskite thin films remains intact despite high KI concentration levels. Charge transport studies of doped 2D perovskite thin films demonstrate a decline in the lifetime of photogenerated charge carriers with an increase of iodide concentration. Combining several experimental and computational techniques, we find that increased carrier effective masses and consequent formation of strongly bound excitons cause the decrease in carrier lifetime. In short, our present study reveals a promising low-cost solution-processable approach to fabricate single-phase mixed halide 2D perovskites to achieve unprecedented exciton tunability in low-dimensional optoelectronic materials.

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