Heterojunctions and devices of colloidal semiconductor films and quantum dots

Abstract

We present an electrical characterization of thin film semiconductor devices based on porous nanocrystalline TiO2 anatase films. It is shown that the TiO2 films can be doped, and that injecting or blocking electrical contacts can be established by metals, semiconductors, and oxides. This opens the way for the preparation of a number of all-solid-state devices. We present results on a Schottky barrier, a two-layer heterojunction on amorphous silicon, and a distributed heterojunction involving PbS quantum dots adsorbed on the internal surface of the TiO2 film.

Solar Energy Materials

“…[356] A number of absorbers including Se (IPCE ¼ 16.1%, Z ¼ 0.13%, V OC ¼ 600 mV, J SC ¼ 3.0 mA cm À2 at 800 W m À2 ), [357] CdS (0.4%), [357] In 2 S 3 (3.4%), [358,359] [353,360] PbS, [361] a-Si:H (1%), [361] CdTe, [362,363] CdSe (IPCE ¼ 60%, 400-500 nm, APCE $ 100%, Z ¼ 1.3%, J SC ¼ 2.3 mA cm -2 , V OC ¼ 0.86 V, FF ¼ 0.651 sun), [364] (a) [354] with permission from Elsevier HgCdTe, [365] Cu 2-x S(0.06%), [366] and Sb 2 S 3 [367] have been used. p-Type materials such as b-CuSCN and ZnTe fill the voids and complete the device.…”

Temperature dependence of the electron diffusion coefficient in electrolyte-filledTiO2nanoparticle films: Evidence against multiple trapping in exponential conduction-band tails

“…The electrolyte, which fills the pores, is not only essential to the application of this material in solar cells, but also appears to passivate defects that greatly retard electron transport in "dry" mesoporous titania. 14 Technically, diffusion of electrons in the electrolyte-filled material is ambipolar, 6,15 meaning that the mobile electrons in titania carry a cloud of countercharges ͑cations͒ in the electrolyte. This is a well-known phenomenon in the diffusion theory of electrolyte solutions.…”

The Influence of Reactive Gaseous Flow Rate and Composition on the Optical Properties of TiO2Thin Films Deposited by Dc Magnetron

“…This high value for non-linear refractive index leads to new possible applications for TiO 2 thin films in non-linear optics devices. Titanium oxide films are extensively used in optical thin film device applications owing to their desirable optical properties and good stability in adverse environments [9]. Many deposition methods can be used to prepare titanium oxide films [10,11].…”