(Invited) Impact of Indiumand Gallium Doping on the Photovoltaic Performance of CdSe Quantum Dot Hybrid Solar Cells

Abstract

Colloidal CdSe quantum dots show great promise for fabrication of hybrid solar cells with enhanced power conversion efficiency. Here, we demonstrate that gallium-, indium-, tin-doped CdSe quantum dots show significantly improved conductivity and charge carrier density, and also temperature dependent behavior. Furthermore, the doped CdSe hybrid solar cells greatly enhance photocurrent and photovoltage, in which the gallium doped CdSe quantum dots and P3HT bi-layer heterojunction solar cells leads to a maximum power conversion efficiency of 2.0% at elevated temperatures under AM 1.5 solar illumination. All the doped samples exhibit inverted temperature dependent power conversion of the photovoltaic cells, which could be effectively utilized in solar concentrators. The approach presented can be applied to a wide range of doped quantum dots and polymer hybrids and is compatible with solution processing, thereby offering a general tactic for improving the efficiency of quantum dot based solar cells.The so called 3rd generation solar cells have been the interest of the scientific community with a promise of providing cheap and efficient photovoltaic devices. 1-4 One of the 3rd generation solar cell concepts depends on a combination of inorganic and organic photosensitizers. 5-8 The inorganic components can consist of quantum confined semiconductor structures 3, 9 (nanoparticle, nanorod, tetrapods) that are synthesized via colloidal route combined with conductive polymers such as P3HT. 10, 11 Varying the composition, size and shape of the inorganic component these photovoltaic cells allows capturing and utilizing photons from different parts from the solar output. While these solar cells are proven to be functional, it is difficult to manufacture them with high overall power conversion efficiencies; therefore, research needs to focus on concepts that can identify components that are responsible for the lack of improvements.Among the quantum dot (QD) materials, CdSe QDs received significant attention in this quest of producing efficient solar cells. Although CdSe is not a sustainable material, it provides a platform to study many different effects associated with the construction of polymer/inorganic solar cells. 3 In addition, the bandgap of colloidal CdSe QDs (2.6-1.7 eV) overlaps reasonably well with the solar output to capture large portion of the sunlight's energy. There are several reports that show P3HT/CdSe QDs solar cells provide somewhat efficient power conversion efficiencies in the few percent range. 9, 12-25 Recently, Zhou et al. have reached 5.3% record power conversion efficiency in PCPDTBT: CdSe device as a result of removal of trap sites upon the ethanedithiol 10.1149/06615.0001ecst ©The Electrochemical Society ECS Transactions, 66 (15) 1-8 (2015) 1 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 137.122.8.73 Downloaded on 2015-08-06 to IP

Atomic Force Microscopy-Based Static Plowing Lithography Using CaCO3 Nanoparticle Resist Layers as a Substrate-Flexible Selective Metal Deposition Resist

“…The development of substrate-tolerant methods for precise fabrication of metal micro- and nanostructures has broad utility for applications including energy harvesting and storage, − biosensing, as well as photonic and plasmonic materials. − Here, the development of novel salt-based resist films is explored to ultimately increase the versatility of fabrication of such metal structures. The combination of the CaCO 3 NP resist films with AFM-based patterning and thermal evaporation of the metal allows for the fabrication of metal structures with a defined size, shape, and position with a range of different substrates.…”

“…In recent years, the fabrication and miniaturization of metallic structures has drawn a lot of attention as the demand for smaller electronic devices and the need to conserve expensive metals increases. Nanomaterials are useful for many different applications, such as miniaturized electronics, biological and plasmonic − sensing devices, surface-enhanced Raman spectroscopy, solar energy applications, − photodetectors, and catalysis. − The properties of metallic nanostructures are highly dependent on their chemical identity, size, and shape. Solution-based synthesis of metallic nanoparticles (NPs) provides a well-defined control over the nanostructures’ size and shape , but lacks the ability to control their placement on a surface.…”