A blue organic near infrared (NIR) absorbing sensitizer, AP25, is investigated for use in broadly absorbing dye-sensitized solar cells (DSCs).

An organic dye with three electron donating groups is studied that has broad full visible spectrum panchromatic absorption in solution. The donor groups introduce six significant optical transitions spaced throughout the visible spectrum to give a dye with near uniform molar absorptivity across the visible spectrum. This unique material is characterized by optical, electrochemical, and computational methods. Within dye-sensitized solar cell (DSC) devices, this material shows a strong photocurrent output of ∼20 mA/cm2 with no cosensitization. DSC devices are characterized through impedance spectroscopy, current–voltage curve analysis, and incident photon-to-current conversion efficiency measurements. Importantly, minimal DSC device performance loss is observed after 500 h of continuous irradiation.

No abstract

The bulky triarylamine group commonly referred to as the "Hagfeldtd onor" is ak ey buildingb lock found in many of the organic dyes used in dye-sensitized applications such as dyesensitized solar cells (DSCs). This building block has gained popularity owing to its presence in many of the best-performing DSC devicesr eported to date, which use dyes containing this donorg roup. The Hagfeldt donor provides ad esirable 3dimensionals tructure that aids in surface protection of electrons injected into the semiconductor from oxidants in the electrolyte, allowing for record-setting cobalt-and copperbased redoxs huttles to be utilized more frequently.H owever, the synthesiso ft his molecule has provenu nreliable form any routes. This study concerns an ovel, reliable and scalable fivestep synthesis of the Hagfeldt donor.Supporting Information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

A series of iron polypyridyl redox shuttles were synthesized in the 2+ and 3+ oxidation states and paired with a series of wide optical gap organic dyes with weak aryl ether electron‐donating groups. High voltage dye‐sensitized solar cell (HV‐DSC) devices were obtained through controlling the redox shuttle energetics and dye donor structure. The use of aryl ether donor groups, in place of commonly used aryl amines, allowed for the lowering of the dye ground‐state oxidation potential which enabled challenging to oxidize redox shuttles based on Fe2+ polypyridyl structures to be used in functional devices. By carefully designing a dye series that varies the number of alkyl chains for TiO2 surface protection, the recombination of electrons in TiO2 to the oxidized redox shuttle could be controlled, leading to HV‐DSC devices of up to 1.4 V.

Mechanically stacked single illuminated area sequential series multijunction dye-sensitized solar cells (SSM-DSCs) were fabricated with varying bottom devices including DSC, silicon (Si), and gallium arsenide (GaAs). The use of near-infrared (>750 nm) photons for conversion into electricity is probed for each of the three technologies. The effect of using these photons on multijunction device power conversion efficiencies is investigated with a three-subcell SSM-DSC design where the top and middle subcells were DSC devices with D35 and B11 sensitizers, respectively. The power conversion efficiencies were found to follow the order: DSC/DSC/GaAs > DSC/DSC/DSC > DSC/DSC/Si. Low-light conditions were examined for the third subcell technologies as independent solar cells to understand the effects of receiving low light intensity as part of a multijunction system. GaAs and DSC as bottom devices both demonstrated a superior response under filtered or reduced illumination to that of Si in these studies. The influence of harsh temperatures on DSC device performance was also examined.

No abstract

No abstract