K.D.M. Rao

Indian Association for the Cultivation of Science · School of Applied & Interdisciplinary Science (SAIS)

Halide perovskites offer a transformative potential for optoelectronics through tailoring the light‐matter interactions at the nanoscale. However, their susceptibility to environmental factors and limited compatibility with standard lithography techniques present significant challenges in precise nanopatterning. This work unveils a nature‐inspired...

Despite substantial advancements in n-type 1D and 2D nanostructures, achieving p-type field-effect transistors (FETs) using 1D nanostructures remains a formidable challenge due to surface defects and doping limitations. This study presents a scalable approach for fabricating the p-type homojunction (p/p+) CuI nanoribbons (CuI NRs) with enhanced cha...

In the contemporary way of life, face masks are crucial in managing disease transmission and battling air pollution. However, two key challenges, self-sanitization and biodegradation of face masks, need immediate attention, prompting the development of innovative solutions for the future. In this study, we present a novel approach that combines con...

Facet‐orientated double perovskite (DP) microcrystals (MCs) are of particular interest in optoelectronics due to the special symmetry and homogeneous interfaces, which extend the carrier lifetime and enhance the mobility to realize robust device performance. Here, a simple hot‐spin casting method is developed to instantaneously synthesize the highl...

Transparent and wearable devices have aroused immense research interest for their widespread applications, however, the fabrication of electrically and thermally homogeneous devices is an outstanding challenge to manifest low-power wearable thermotherapy devices. Here, we developed simple angled-stencil lithography to fabricate Ag micro-mesh based...

The emergence of organic-inorganic hybrid perovskites (OHPs) has revolutionised the potential performance of optoelectronic devices, most perovskites are opaque and hence incompatible with transparent optoelectronics, and sensitive to environmental degradation. Here, a single-step fabrication of ultra-long MAPbI3 perovskite microwire array over a l...

Unveiling the transparency and flexibility in perovskite-based photodetectors with superior photoresponse and environmental stability remains an open challenge. Here we report on the guanidinium incorporated metal halide perovskite (MA1-xGuaxPbI3, x=0 to 0.65) random percolative microstructures (RPMs) fabrication by a single step using ultra-fast s...

Desiccation of a colloidal layer produces crack patterns due to stress arising out of solvent evaporation. Associated with it is the rearrangement of particles while adhesion to the substrate resisting such movements. The nature of solvent which is often overlooked plays a key role in the process as it dictates evaporation and wetting properties of...

The development of self‐powered and broadband (NIR–Vis–UV) photodetectors with high responsivity is essential for energy efficient futuristic optoelectronic devices. A simple approach is reported to formulate inorganic–organic (GaN/rGO: Ag NP) hybrid p–n heterojunction photodetectors clasping with transparent Au nanowire network as the top electrod...

High-performing large-area photodetectors are essential for optoelectronic applications. However, the existing photodetectors are limited to small areas, and at larger areas, the response slows down because of increased device capacitance. Capturing photon flux over a large area is particularly important for low-light conditions. Here we report a s...

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Monitoring live movements of human body parts is becoming increasingly important in the context of biomedical and human machine technologies. The development of wearable strain sensors with high sensitivity and fast response is critical to addressing this need. In this article, we describe the fabrication of a wearable strain sensor made of a Au mi...

Despite relatively high manufacturing cost, crystalline-Si solar cell continues to hold promising future due to its high energy conversion efficiency and long life. As regards cost, one pertinent issue is the top electrode metallization of textured cell surface, which typically involves screen printing of silver paste. The associated disadvantages...

High degree of transparency in devices is considered desirable for futuristic technology. This demands that both the active material and the electrodes are made of transparent materials. In this work, a transparent Pd wire network fabricated using crackle lithography technique over ~ 1 cm(2), with sheet resistance and transmittance of ~ 200 Ω □(-1)...

Heater plates or sheets that are visibly transparent have many interesting applications in optoelectronic devices such as displays, as well as in defrosting, defogging, gas sensing and point-of-care disposable devices. In recent years, there have been many advances in this area with the advent of next generation transparent conducting electrodes (T...

Resistive random access memory (RRAM) is the most promising candidate for next generation nonvolatile memory. In this article, resistive switching in PdO thin film is investigated. The fabricated in-plane devices showed voltage pulse induced multilevel resistive switching (MRS) with as many as five states under ambient conditions with high degrees...

In the quest for indium-tin oxide (ITO)-free photovoltaics and for building integrated as well as automobile roof applications, novel transparent electrodes for both front and back electrodes are required. Here we report the fabrication and integration of submicrometer transparent silver (Ag) and gold (Au) metal network electrodes, which are invisi...

A single micro/nanowire network of a metal deposited over a large area on a transparent substrate serves as a transparent conducting electrode with optoelectronic properties that are enhanced in many ways relative to the conventional indium tin oxide films. The wire surface is extremely smooth and the junctions are seamless, thanks to the crackle l...

Transparent conducting electrodes (TCEs) have been made on flat, flexible, and curved surfaces, following a crack template method in which a desired surface was uniformly spray-coated with a crackle precursor (CP) and metal (Ag) was deposited by vacuum evaporation. An acrylic resin (CP1) and a SiO2 nanoparticle-based dispersion (CP2) derived from c...

As transparency is becoming a desirable property even in non-optoelectronic devices, there is great impetus given to alternate materials and strategies replacing the conventional ITO. Here we have used transparent Au wire networks as electrodes, obtained from a crackle template method, in a capacitor where an ion gel serves as the dielectric. The t...

We report a highly transparent, low resistant Ag metal network templated from a cracked polymer thin film and its incorporation in an organic solar cell. The performance of this scalable metallic network is comparable to that of conventional ITO electrode. This is a general approach to replace ITO in diverse thin film devices.

A transparent conductor which can generate high temperatures finds important applications in optoelectronics. In this article, a wire network made of Au on quartz is shown to serve as an effective high temperature transparent heater. The heater has been fabricated by depositing Au onto a cracked sacrificial template. The highly interconnected Au wi...

A metal (Au) wire network, nearly invisible to the naked eye, has been realized on common substrates such as glass, to serve as a transparent conducting electrode (TCE). The process involves coating a TiO2 nanoparticle dispersion to a film thickness of ~10 μm, which following solvent evaporation, spontaneously forms a crackle network; the film is t...

Virtually unlimited and highly interconnected Cu wire networks have been fabricated on polyethylene terephthalate (PET) substrates with sheet resistance of <5 Ω −1 and transmittance of 75%, as alternatives to the commonly used tin doped indium oxide (ITO) based electrodes. This is a four step process involving deposition of commercially available c...

As transparency is becoming a desirable property even in non-optoelectronic devices, there is great impetus given to alternate materials and strategies replacing the conventional ITO. Here we have used transparent Au wire networks as electrodes, obtained from a crackle template method, in a capacitor where an ion gel serves as the dielectric. The t...

As solar cell modules are becoming larger, it is important to pay attention to defects originating from the fabrication process and degradation during operation in the ambient. In this article, a simple method of using computer screen display as a light source to map the photoresponse of the solar cells, is reported. The method requires only a conv...

We report a simple lithography-free, solution-based method of soldering of carbon nanotubes with Ohmic contacts, by taking specific examples of multi-walled carbon nanotubes (MWNTs). This is achieved by self-assembling a monolayer of soldering precursor, Pd(2+) anchored to 1,10 decanedithiol, onto which MWNTs could be aligned across the gap electro...

Thermolysis of Ni butanethiolate in a sulfur atmosphere has been carried out at 300 and 600 °C to produce NiS2 nanocrystalline films with mean crystallite sizes of 16 and 192 nm and resistivity values of 451 and 3540 μΩ·m, respectively; the resistivity values are 2 orders of magnitude less compared to the bulk value (12000 μΩ·m). This is a signific...