eprintid: 29225
rev_number: 16
eprint_status: archive
userid: 5605
dir: disk0/00/02/92/25
datestamp: 2020-12-15 14:58:16
lastmod: 2021-01-19 08:12:28
status_changed: 2020-12-15 14:58:16
type: doctoralThesis
metadata_visibility: show
creators_name: An, Qingzhi
title: Physics of Interfaces in MAPbI3 Perovskite Solar Cells
subjects: 530
divisions: 130700
adv_faculty: af-13
cterms_swd: Perovskite Photovoltaics
abstract: Interfaces in perovskite solar cells, such as interfaces between adjacent layers or at grain bound- aries, play an important role in determining the performance of photovoltaic devices. This thesis describes investigations of the physical properties of several such interfaces in order to elucidate their influence on the photovoltaic devices and further utilize this knowledge to improve the device performance. First, we investigate the interface between a perovskite active layer and a ZnO elec- tron transport layer. We demonstrate that this interface strongly influences the microstructure of polycrystalline perovskite. Using a combination of doping and modification by a self-assembled monolayer, we optimize both the bulk and surface properties of the ZnO layer, leading to a su- perior perovskite layer microstructure and a doubling of the photovoltaic performance. Next, we investigate the interface between an organic electron transport layer and the metal cathode. We modify this interface by inserting a series of newly synthesized π -extended phosphoniumfluorene electrolytes and demonstrate that such modification significantly increases the built-in potential of the device by compensating for the non-ideal energetic alignment caused by the other device layers. Consequently, the modified devices exhibit an increase in the open-circuit voltage by up to 120 mV. Finally, we systematically investigate the effects of grain boundaries on the performance of perovskite solar cells by combining the experimental characterizations and the theoretical de- vice simulations. We show that grain boundaries contribute to the non-radiative recombination losses in perovskite solar cells and the small grains serve as recombination ’hot spots’ that limit the open circuit voltage, as well as the performance of the devices.
date: 2020
id_scheme: DOI
id_number: 10.11588/heidok.00029225
ppn_swb: 1743001223
own_urn: urn:nbn:de:bsz:16-heidok-292252
date_accepted: 2020-12-10
advisor: HASH(0x55611e72af98)
language: eng
bibsort: ANQINGZHIPHYSICSOFI2020
full_text_status: public
place_of_pub: Heidelberg
citation:   An, Qingzhi  (2020) Physics of Interfaces in MAPbI3 Perovskite Solar Cells.  [Dissertation]     
document_url: https://archiv.ub.uni-heidelberg.de/volltextserver/29225/7/Dissertation%20Qingzhi%20An.pdf