Investigation on Photovoltaic Performance based on Matchstick-Like Cu2S–In2S3Heterostructure Nanocrystals and Polymer

In this paper, we synthesized a novel type II cuprous sulfide (Cu2S)–indium sulfide (In2S3) heterostructure nanocrystals with matchstick-like morphology in pure dodecanethiol. The photovoltaic properties of the heterostructure nanocrystals were investigated based on the blends of the nanocrystals and poly(2-methoxy-5-(2′-ethylhexoxy)-p-phenylenevinylene) (MEH-PPV). In comparison with the photovoltaic properties of the blends of Cu2S or In2S3nanocrystals alone and MEH-PPV, the power conversion efficiency of the hybrid device based on blend of Cu2S–In2S3and MEH-PPV is enhanced by ~3–5 times. This improvement is consistent with the improved exciton dissociation or separation and better charge transport abilities in type II heterostructure nanocrystals

Organic-Inorganic Nanostructure Architecture via Directly Capping Fullerenes onto Quantum Dots

A new form of fullerene-capped CdSe nanoparticles (PCBA-capped CdSe NPs), using carboxylate ligands with [60] fullerene capping groups that provides an effective synthetic methodology to attach fullerenes noncovalently to CdSe, is presented for usage in nanotechnology and photoelectric fields. Interestingly, either the internal charge transfer or the energy transfer in the hybrid material contributes to photoluminescence (PL) quenching of the CdSe moieties.open2

A nanocomposite ultraviolet photodetector based on interfacial trap-controlled charge injection

Ultraviolet photodetectors have applications in fields such as medicine, communications and defence1, and are typically made from single-crystalline silicon, silicon carbide or gallium nitride p–n junction photodiodes. However, such inorganic photodetectors are unsuitable for certain applications because of their high cost and low responsivity (<0.2 A W−1)2. Solution-processed photodetectors based on organic materials and/or nanomaterials could be significantly cheaper to manufacture, but their performance so far has been limited2,3,4,5,6,7. Here, we show that a solution-processed ultraviolet photodetector with a nanocomposite active layer composed of ZnO nanoparticles blended with semiconducting polymers can significantly outperform inorganic photodetectors. As a result of interfacial trap-controlled charge injection, the photodetector transitions from a photodiode with a rectifying Schottky contact in the dark, to a photoconductor with an ohmic contact under illumination, and therefore combines the low dark current of a photodiode and the high responsivity of a photoconductor (∼721–1,001 A W−1). Under a bias of <10 V, our device provides a detectivity of 3.4 × 1015 Jones at 360 nm at room temperature, which is two to three orders of magnitude higher than that of existing inorganic semiconductor ultraviolet photodetectors

The effect of three-dimensional morphology on the efficiency of hybrid polymer solar cells

The efficiency of polymer solar cells critically depends on the intimacy of mixing of the donor and acceptor semiconductors used in these devices to create charges and on the presence of unhindered percolation pathways in the individual components to transport holes and electrons. The visualization of these bulk heterojunction morphologies in three dimensions has been challenging and has hampered progress in this area. Here, we spatially resolve the morphology of 2%-efficient hybrid solar cells consisting of poly(3-hexylthiophene) as the donor and ZnO as the acceptor in the nanometre range by electron tomography. The morphology is statistically analysed for spherical contact distance and percolation pathways. Together with solving the three-dimensional exciton-diffusion equation, a consistent and quantitative correlation between solar-cell performance, photophysical data and the three-dimensional morphology has been obtained for devices with different layer thicknesses that enables differentiating between generation and transport as limiting factors to performance.

Photovoltage method for the research of CdS and ZnO nanoparticles and hybrid MEH-PPV/nanoparticle structures

The paper demonstrates an application of photovoltaic effect in the research of nanomaterials and hybrid structures of polymers with nanoparticles. Photovoltage (PV) measurement was utilized for estimating the size of CdS and ZnO nanoparticles and diagnostics of hybrid structures with poly[2-methoxy-5-(2- ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), namely nano-CdS/MEH-PPV and nano-ZnO/MEH-PPV. CdS average nanocrystal diameters 4.0 and 4.8 nm were calculated from the onset values of energies corresponding to the steep increase in the PV signals using the effective mass model. The range of size of ZnO particles was from about 5 up to 50 nm. Nanoparticle distribution obtained by transmission electron microscopy (TEM) measurements shows that the calculated diameters agree fairly well with the size of nanoparticles with the highest occurrence. The PV spectrum represents a sum of the spectra corresponding to the various nanoparticle sizes. The distribution of the nanoparticles was also obtained by a simple mathematical treatment of the PV spectra, and agreement with the results of TEM was found. PV and TEM measurements were performed on commercial CdS and ZnO nanoparticles and on CdS nanoparticles prepared in our laboratory. We employ triethanolamine as a protective agent to cover the surface of CdS nanoparticles. Nano-CdS/MEH-PPV and nano-ZnO/MeH-PPV hybrid structures were prepared, and influence of the particles on charge transport was shown by the PV spectra measurements. © 2014 Springer Science+Business Media