Annealing-Temperature Dependent Carrier-Transportation in ZnO/PbS Quantum Dot Solar Cells Fabricated Using Liquid-Phase Ligand Exchange Methods

Abstract

We constructed ZnO/PbS quantum dot (QD) heterojunction solar cells using liquid-phase ligand exchange methods. Colloidal QD solutions deposited on ZnO-dense layers were treated at different temperatures to systematically study how thermal annealing temperature affected carrier transport properties. The surface of the layers became dense and smooth as the temperature approached approximately 80 °C. The morphology of layers became rough for higher temperatures, causing large grain-forming PbS QD aggregation. The number of defect states in the layers indicated a valley-shaped profile with a minimum of 80 °C. This temperature dependence was closely related to the amount of residual n-butylamine complexes in the PbS QD layers and the active layer morphology. The resulting carrier diffusion length obtained on the active layers treated at 80 °C reached approximately 430 nm. The solar cells with a 430-nm-thick active layer produced a power conversion efficiency (PCE) of 11.3%. An even higher PCE is expected in solar cells fabricated under optimal annealing conditions.

In Situ Growth of PbS Nanoparticles without Organic Linker on ZnO Nanostructures via Successive Ionic Layer Adsorption and Reaction (SILAR)

“…The peak in the yellow zone is known to be related to deep effects (oxygen interstitials) at 584 nm. The intensity ratios of NBE to DLE for the green emission are 7.2, 3 and 10.1, respectively, which shows that the intensity of the green emission is lower at higher concentrations, while the DLE occurred a red shift with a decrease in the intensity of the PL at 16 cycles, due to the increase in the size of the PbS nanoparticles and their aggregation [44]. On the other hand, the intensity ratios of NBE to DLE for the yellow emission are 20, 6.86 and 12, respectively, according to the number of SILAR cycles.…”

Эффект Интерфейсного Легирования Системы Наностержней Оксида Цинка

“…Электронный тип проводимости ZnO при отсутствии примесных атомов связывают с собственными точечными дефектами, преимущественно с вакансиями кислорода и междоузельными атомами Zn [1]. Нелегированные слои ZnO используются как прозрачный электронно-транспортный слой в фотовольтаических структурах [2][3][4]. Легирование ZnO атомами Al или Ga обеспечивает использование слоев ZnO в качестве прозрачных проводящих электродов [5][6][7][8].…”

Interface doping of zinc oxide nanorods

“…The electron type of ZnO conductivity without doping is associated with its intrinsic point defects, predominantly vacancies of oxygen and Zn interstitials [1]. Undoped layers of ZnO are used as a transparent electrontransport layer in photovoltaic structures [2][3][4]. Doping of ZnO with Al or Ga atoms provides for the use of ZnO layers as transparent conductive electrodes [5][6][7][8].…”