Comprehensive control of voltage loss enables 11.7% efficient solid-state dye-sensitized solar cells

Abstract

The relatively large voltage loss (V loss ) in excitonic type solar cells severely limits their power conversion efficiencies (PCEs). Here, we report a comprehensive control of V loss through efficacious engineering of the sensitizer and redox mediator, making a breakthrough in the PCE of dye-sensitized solar cells (DSSCs).The targeted down-regulation of V loss is successfully realized by three valid channels: (i) reducing the driving force of electron injection through dye molecular engineering, (ii) decreasing the dye regeneration overpotential through redox mediator engineering, and (iii) suppressing interfacial electron recombination.Significantly, the ''trade-off'' effect between the dye optical band gap and the open-circuit voltage (V OC ) is minimized to a great extent, achieving a distinct enhancement in photovoltaic performance (PCE 4 11.5%with V OC up to 1.1 V) for liquid junction cells. The solidification of the best-performing device leads to a PCE of 11.7%, which is so far the highest efficiency obtained for solid-state DSSCs. Our work inspires further development in highly efficient excitonic solar cells by comprehensive control of V loss . Broader contextExcitonic type solar cells, including dye-sensitized solar cells (DSSCs), perovskite solar cells (PSCs) and organic solar cells (OSCs), are potential alternatives for photovoltaic applications. To further advance their power conversion efficiencies (PCEs), it is crucial to reduce the so called voltage loss (V loss ) as much as possible. In DSSCs, the V loss mainly takes place in the electron injection, dye regeneration and interfacial recombination processes, whereas the targeted decreasing of V loss in all these aspects has been rarely reported. To address this issue, we herein demonstrate a comprehensive control of V loss , achieving 11.7% efficiency for solid-state DSSCs. This work is a good example of radically improving the PCE through rationally reducing V loss .

Electron‐Affinity‐Triggered Variations on the Optical and Electrical Properties of Dye Molecules Enabling Highly Efficient Dye‐Sensitized Solar Cells

“…[1][2][3][4][5] In the past few decades,P CEs of DSCs have been pushed from about 7% to around 14 %. [6][7][8][9][10][11][12] Highefficiency low-cost DSCs are required to be able to commercialize this technology.O ne way of achieving such goal is through the development of dye molecules,which can harvest more photons while maintaining high photovoltages. [13][14][15] In this regard, systematic studies on the structure-electrochemical property relationship are critically important.…”

Phenanthrene‐Fused‐Quinoxaline as a Key Building Block for Highly Efficient and Stable Sensitizers in Copper‐Electrolyte‐Based Dye‐Sensitized Solar Cells

“…Moreover, these Cu II/I bipyridyl or phenanthroline complexes exhibit very low reorganization energies to allow the regeneration of sensitizers to proceed rapidly at low driving force . However, the moderate value of short‐circuit current densities ( J SC ) in copper‐based DSSCs becomes the bottleneck for further PCE improvement . Indeed, the current lack of sensitizers with extended long‐wavelength response prevents the full potential of the copper redox shuttles from being exploited.…”

“…There have already been attempts to employ benzothiadiazole (BT) or quinoxaline as the auxiliary acceptors to widen the spectral response of sensitizers for copper‐based DSSCs. However, these dyes have not delivered the desired J SC increase …”

Dual Quantum Dot‐Decorated Bismuth Vanadate Photoanodes for Highly Efficient Solar Water Oxidation

“…Besides photo‐induced charge separation, photon absorption is another significant factor influencing the PEC performance . Generally, photosensitizers such as CdS/CdTe QDs, layered black phosphorous, and ruthenium/rhenium‐based dye are employed in photocatalysis, photoelectrocatalysis, and solar cells to broaden photon‐absorption range . However, they are either toxic or unstable for practical applications.…”

“…[11,20] Generally,p hotosensitizers such as CdS/CdTe QDs, layered black phosphorous, and ruthenium/rheniumbased dye are employed in photocatalysis, photoelectrocatalysis, and solar cells to broaden photon-absorption range. [20][21][22][23] However, they are either toxic or unstable for practical applica-Photo-induced charges eparation and photon absorption play important roles in determining the performance of the photoelectrocatalytic water splitting process. In this work, we utilize dual quantum dots (QDs), consisting of BiVO 4 and carbon,t o fabricateahybrid homojunction-based BiVO 4 photoanode for efficient and stable solar water oxidation.…”