No abstract

An enormous amount of development has been made in the field of photovoltaics in the last 50 odd years. In recent years, the uses of semiconductor nanoparticles have given a new impetus and direction to research in the field of solar cells. This is due to the excellent photoemission properties shown by semiconductors in the quantum dot (QD) state. ZnS QDs show a further interesting feature where their photoemission properties show perceivable changes on adding dopants such as nickel. In the present work, we describe the characterization studies made on Ni:ZnS thin films using photoluminescence (PL), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), and further reports their performance as an absorbing layer in a hybrid solar cell along with poly(3-hexylthiophene) (P3HT). Fabricated Ni:ZnS cell showed a conversion efficiency of 0.25 ± 0.05% with VOC and JSC of 560 mV and 0.11 mA/cm2, respectively. Although the absolute conversion efficiency appears low (only 0.25%), the addition of nickel was found to have improved the efficiency by a hundredfold compared with undoped ZnS.

Perovskite thin films hold promise as a potential candidate for high efficiency solar cells. In recent years, a wealth of results has been published on CsPbI3 thin films. However, most of the literature reports that CsPbI3 perovskite films are prone to aging where black colored CsPbI3 films with cubic lattice change to yellow colored films with orthorhombic lattice upon exposure to ambient conditions. This poor stability presents itself as a major challenge in utilization of CsPbI3 for device applications. This manuscript presents an alternate route for fabricating stable CsPbI3 thin films using thermal evaporation. Experimentally, our samples were found to be stable, visually and structurally, over a period of six months. Even annealing of the samples did not induce structural changes.

In the present work, indium tin oxide (ITO)/n‐CdS/p‐SnS/Au structured solar cells are fabricated with best conversion efficiency of 0.005%. A detailed investigation is made into the cause of the poor conversion efficiency and the cause is narrowed down to defects in p‐SnS which effect the junction and the neutral region of the cell. The junctions performance is quantified using the ideality factor which is found to be related to the band misalignment. The paper also investigates into literature and discusses efforts made to overcome the problems with this structure.

The manuscript looks into the improvement of Life Expectancy and the number of invention patents filed in USA over the last two centuries. The direct proportionality between Technological advancement and Life Expectancy proves that the two indices are co­related. However, the co­relation when viewed with the lag present between Life Expectancy and Technological advancement indicates that the Technological advancement depends on the Life Expectancy and not visa versa. This notionally proves increased Life expectancy as the cause to Technological developments being made in USA.