Page 60 - Annual Report_21-22

Development of lead-free perovskites for optoelectronic applications
Exploring prospective materials for energy production and perovskites (HPs) for PV&OE applications. Chalcogenide
storage is currently the major challenge in our modern perovskites (CPs) and titanium-based HPs that combine
civilization. Solar energy is one of the most important all the desirable attributes for PV&OE applications e.g.,
renewable energy resources having wide availability and ease of synthesis, high band edge absorption, long charge
low environmental impact. Lead halide perovskites (LHPs) carrier lifetime, longer and balanced carrier diffusion
have emerged as a class of semiconductor materials length, high stability and no toxicity, are extremely
with unique properties, including tunable bandgap, high rare. However theoretical calculations considering
absorption coefficient, broad absorption spectrum, high the perovskite formation energy are showing ample
charge carrier mobility and long charge carrier diffusion opportunities to synthesize CPs and Ti based HPs. We will
lengths, which enable a broad range of photovoltaic develop new synthetic strategies to synthesize new CPs
and optoelectronic (PV&OE) applications. However, (ABS -A is Ba and B is bivalent cation Zr , Hf ) and Ti
2+
2+
2+
3
there are certain limitations to commercialize the LHPs based double HPs (A TiX where A = K+,Rb+,Cs+,In+,MA+,
6
2
due to their instability, toxicity and large area efficient or FA+; X = Cl , Br , or I ) quantum dots (QDs) at the nano-
-
-
-
device fabrications. Therefore, significant efforts are scale by atomic scale chemical engineering of the nontoxic
being devoted to the search for all-inorganic lead-free elements.

Figure: Schematic of possible band and crystal structures of CPs and Ti based HPs.

Development of Sustainable Cold Spray Coatings for repairing process and tribological
application
Different materials such as metals, ceramics, composites deposition, dense structures, and minimal or compressive
and polymers can be deposited using Cold Spray, residual stress. In addition to these characteristics, the
creating a wealth of interesting opportunities towards deposited material possesses strength close to that
harvesting particular properties. Cold Spray is a novel and of wrought material. The limited deformation of hard
promising technology to obtain surface coating, offering cermet particles and impacted coating makes it difficult
several technological advantages over thermal spray for conventional thermal spray powders to continuously
since it utilizes kinetic rather than thermal energy for build up on impact in cold spraying. The use of designed
deposition. As a result, tensile residual stresses, oxidation nanostructured porous cermet will create an avenue for
and undesired chemical reactions can be avoided. building up of dense coating at high deposition efficiency
The attributes of cold spray include low temperature and offer enhanced wear resistance.

Figure: XRD & Microstructure of Cold Sprayed Cu+Zr on MS
58 ANNUAL REPORT 2021-22