Photocurrent Enhancement from Solid-State Triplet–Triplet Annihilation Upconversion of Low-Intensity, Low-Energy Photons

Abstract

We present a red-to-blue upconversion system based on triplet–triplet annihilation in a solid-state film configuration that significantly enhances the photocurrent of a model solar cell device. The film is robust against oxygen quenching and can be readily tailored to existing solar cell architectures. The photovoltaic performance of upconversion-assisted dye-sensitized photoelectrochemical cells was measured under both high-power coherent laser and low-power incoherent light irradiation (light-emitting diode and simulated AM1.5G sunlight). By utilizing low-energy photons that would otherwise be wasted, the photocurrent is enhanced by as much as 35% under one-sun light intensity when a model solar cell device is coupled with a TTA film and a reflector.

Optimizing photon upconversion by decoupling excimer formation and triplet triplet annihilation

“…34 TTA-UC systems based on perylene as the annihilator hold the photon upconversion quantum yield record and have now been used in solar cells, photo-redox catalysis and bio-imaging. 18,[35][36][37] The drawback of perylene is its tendency to form excited dimers (excimers). Excimer formation in TTA-UC reduces the overall energy conversion efficiency, both due to the lower energy of the emitted photons and due to the significant rate constant of non-radiative decay from excimers.…”

Robust triplet–triplet annihilation photon upconversion by efficient oxygen scavenging

“…Some of the potential solutions to this problem include high-viscosity matrices with low oxygen permeability. [5][6][7][8] Similarly, protective coating has been applied to rubbery matrices to isolate the TTA-UC system from oxygen as well as (organic) silica-coating to semi-fluid systems in liposomes. 9,10 So far, the highest robustness has been found in a system without solvent where the annihilator has been modified to act as a viscous solvent itself.…”

Single Platinum Atom Doping to Silver Clusters Enables Near‐Infrared‐to‐Blue Photon Upconversion

“…Photon upconversion based on triplet–triplet annihilation (TTA‐UC), which converts two low‐energy photons into a high‐energy photon, is currently the sole mechanism that operates at a low photon flux such as solar irradiance. Hence, TTA‐UC has drawn significantly increased interest toward applications in solar cells, [1, 2] photocatalysis, [3, 4] and bioimaging [5] . For such applications, efficient upconversion (UC) from near‐infrared (NIR) to visible or ultraviolet light is particularly important [6] .…”