Vacuum-deposited perovskite photodetectors
- Autores: Lucía Martínez Goyeneche
- Directores de la Tesis: Michele Sessolo (dir. tes.), Daniel Tordera Salvador (codir. tes.)
- Lectura: En la Universitat de València ( España ) en 2024
- Idioma: español
- Tribunal Calificador de la Tesis: Francisco Palazón Huet (presid.), Alicia Forment-Aliaga (secret.), Nicola Gasparini (voc.)
- Programa de doctorado: Programa de Doctorado en Nanociencia y Nanotecnología por la Universidad de Alicante; la Universidad de Castilla-La Mancha; la Universidad de La Laguna; la Universidad Jaume I de Castellón y la Universitat de València (Estudi General)
- Materias:
- Enlaces
- Tesis en acceso abierto en: TESEO
- Resumen
In the mid-20th century, the third technological revolution arrived with the development of new semiconductor materials. Because of it, nowadays we can find devices that are able to open doors automatically or complex arrays capable of detecting radiation from very far places of the universe. These devices, known as photodetectors, detect light and convert it into electrical signals. Different types of semiconductors have been applied as active layer in photodetectors, in particular silicon or III-V semiconductors, that exhibit remarkable optical and electrical properties leading to high performance devices and are compatible with large scale production and miniaturization. However, they show other important disadvantages, in particular the lack of mechanical flexibility, and energy-demanding manufacturing process due to highly pure starting materials and high temperature deposition processes. Alternative materials have been investigated to develop high-performance photodetectors that are compatible with flexible substrates, and that can be processed into thin film at low temperatures and on large scale. The main families of materials are organic semiconductors, metal halide perovskites and inorganic nanocrystals and quantum dots. Among these semiconductors, perovskites show higher charge mobility and diffusion length, resulting in higher EQE and speed response compared to the organic materials.
In this thesis, high-performance and novel perovskite photodetectors have been developed by vacuum deposition technique, which is seldom reported in the literature for perovskite optoelectronics. Several photodetectors with different structures and spectral response width have been fabricated by vacuum evaporation techniques, which allow the fabrication of multilayer devices with accurate layer thickness, in contrast to solution-processing. In view of this, a novel narrowband photodetector characterized by a monolithic tandem structure, with two electrically connected perovskite photodetectors. Using a wider bandgap perovskite in the front terminal leads to narrowband response in the near infrared region and high sensitivity to weak light signals. The same concept was used to fabricate a lateral photoconductor composed of two different perovskites, that operates in broadband and narrowband modes, depending on the illumination side. The selective wavelength response is centered in the near-infrared region.
The reduction of the dark and noise current of a perovskite photodetector is of paramount importance to obtain devices that are highly sensitive to weak light signals. Finally, the effect of the type of hole transport layer on the performance of perovskite photodiodes has been studied. Using a combination of doped and intrinsic organic semiconductors as selective transport layers, very low dark and noise current are achieved. The photodiodes are further tested as X-ray detectors, achieving a linear response in a wide range of X-ray irradiance.
