Optical Resonance Engineering for Infrared Colloidal Quantum Dot Photovoltaics

Abstract

We report optically enhanced infrared-harvesting colloidal quantum dot solar cells based on integrated Fabry–Perot cavities. By integrating the active layer of the photovoltaic device between two reflective interfaces, we tune its sensitivity in the spectral region at 1100–1350 nm. The top and bottom electrodes also serve as mirrors, converting the device into an optical resonator. The front conductive mirror consists of a dielectric stack of SiN x and SiO2 with a terminal layer of ITO and ZnO in which current can flow, while the back mirror consists of a highly reflective gold layer. Adjusting the reflectivity and central wavelength of the front mirror as well as the thickness of the active layer allowed increases in absorption by a total of 56% in the infrared, leading to a record external quantum efficiency of 60% at 1300 nm. This work opens new avenues toward low-cost, high-efficiency rear-junction photovoltaic harvesters that add to the overall performance of silicon solar cells.

Multibandgap quantum dot ensembles for solar-matched infrared energy harvesting

“…The resulting reflection contributes to the device absorptance and introduces resonant absorption. This is due to interference between the forward-propagating light from the illuminated side and the backward-propagating light reflected on the gold electrode and can be controlled and optimized by adjusting the active layer thickness 13 , 32 . We thus measured the total absorption through complete PV devices (Fig.…”

“…In the last decade, intensive efforts have focused on improving CQD synthesis, surface passivation, film formation, and device engineering; and these have led to great strides in increasing the performance of CQD photovoltaics 6 – 12 . IR CQD solar cells, on the other hand, have remained comparatively underexplored, and best IR-filtered PCEs lie below 0.5% 4 , 13 , 14 .…”

Whispering Gallery Mode Enabled Efficiency Enhancement: Defect and Size Controlled CdSe Quantum Dot Sensitized Whisperonic Solar Cells

“…Ouellette et al . 56 showed that by integrating the active layer of the photovoltaic device between two reflective interfaces the solar cells become sensitive for the spectral region at 1100–1350 nm, thus enabling effective IR light extraction. A schematic diagram of QDSWSC cartoon depicting the formation of WGM in SμS-TiO 2 and its effect in PCE along with the FESEM image of SμS-TiO 2 are given Fig.…”

A Facet‐Specific Quantum Dot Passivation Strategy for Colloid Management and Efficient Infrared Photovoltaics

“…Lead chalcogenide narrow-bandgap colloidal quantum dots (CQDs) enable harvesting of infrared (IR) light in single-and multi-junction thin-film solar cells, since their bandgaps can readily be tuned across the solar spectrum by controlling nanocrystal size. [14][15][16][17][18][19][20][21] Advances in the surface chemistry of colloidal nanomaterials have enabled significant progress in the synthesis [22][23][24][25][26][27][28][29] and surface modification [30][31][32][33][34][35][36] of IR CQDs. Recently, lead halide-based solution-phase ligand exchanges on CQDs having a 1.3 eV (~950 nm) bandgap resulted in the highest-performing CQD solar cells to date, with certified power conversion efficiencies (PCEs) reaching 12% under simulated AM1.5 full solar illumination.…”