Origin of Prestress-Driven Optical Modulations of Flexible ZnO Thin Films Processed in Stretching Mode.

Experimental verification of optical modulation with external stress has not been easily available in flexible systems. Here, we intentionally induced extra stress in wide band gap ZnO thin films by a unique prestress-driven deposition processing that utilizes a stretching mode. The stretching mode provides homogeneous but biaxial stresses in the hexagonal wurtzite structure, leading to the extension of the c-axis and the contraction of the a-axis.

High-Efficiency Double Absorber PbS/CdS Heterojunction Solar Cells by Enhanced Charge Collection Using a ZnO Nanorod Array.

The device architecture of solar cells remains critical in achieving high photoconversion efficiency while affordable and scalable routes are being explored. Here, we demonstrate a scalable, low cost, and less toxic synthesis route for the fabrication of PbS/CdS thin-film solar cells with efficiencies as high as ∼5.59%, which is the highest efficiency obtained so far for the PbS-based solar cells not involving quantum dots.

Dynamics of surface evolution in semiconductor thin films grown from a chemical bath.

Dynamics of surface evolution in CdS thin films grown by chemical bath deposition technique has been studied from time sequence of atomic force micrographs. Detailed scaling analysis of surface fluctuation in real and Fourier space yielded characteristic exponents αloc = 0.78 ± 0.

Improved Photovoltaic Characteristics and Grain Boundary Potentials of CuIn0.7Ga0.3Se2 Thin Films Spin-Coated by Na-Dissolved Nontoxic Precursor Solution.

This work introduces the incorporation of Na into the nontoxic precursor solution of CIGS to improve photovoltaic cell performance with the optimized benefits of Na. The extensive incorporation range of 0.05 to 0.

Effect of band-aligned double absorber layers on photovoltaic characteristics of chemical bath deposited PbS/CdS thin film solar cells.

Here we report the highest energy conversion efficiency and good stability of PbS thin film-based depleted heterojunction solar cells, not involving PbS quantum dots. The PbS thin films were grown by the low cost chemical bath deposition (CBD) process at relatively low temperatures. Compared to the quantum dot solar cells which require critical and multistep complex procedures for surface passivation, the present approach, leveraging the facile modulation of the optoelectronic properties of the PbS films by the CBD process, offers a simpler route for optimization of PbS-based solar cells.

Tensile stress-dependent fracture behavior and its influences on photovoltaic characteristics in flexible PbS/CdS thin-film solar cells.

Tensile stress-dependent fracture behavior of flexible PbS/CdS heterojunction thin-film solar cells on indium tin oxide-coated polyethylene terephthalate (PET) substrates is investigated in terms of the variations of fracture parameters with applied strains and their influences on photovoltaic properties. The PbS absorber layer that exhibits only mechanical cracks within the applied strain range from ∼0.67 to 1.

In situ magnetic field-assisted low temperature atmospheric growth of GaN nanowires via the vapor-liquid-solid mechanism.

We report the growth of GaN nanowires at a low temperature of 750 °C and at atmospheric pressure in a conventional chemical vapor deposition (CVD) setup via the vapor-liquid-solid mechanism with remarkable control of directionality and growth behavior by using an in situ magnetic field. Under typical growth conditions, without any magnetic field, the nanowires are severely twisted and kinked, and exhibit a high density of planar stacking defects. With increasing in situ magnetic field strength, the microstructural defects are found to decrease progressively, and quasi-aligned nanowires are produced.

AlN passivation layer-mediated improvement in tensile failure of flexible ZnO:Al thin films.

AlN passivation layer-mediated improvement in tensile failure of ZnO:Al thin films on polyethersulfone substrates is investigated. ZnO:Al films without any passivation layer were brittle with a crack-initiating bending strain εc of only about 1.13% with a saturated crack density ρs of 0.