Unraveling factors leading to efficient norbornadiene–quadricyclane molecular solar-thermal energy storage systems

Abstract

Increased steric bulk in norbornadienes with application in solar energy storage leads to higher quantum yields, red-shifted absorption and higher thermal stability.

Norbornadiene‐Based Photoswitches with Exceptional Combination of Solar Spectrum Match and Long‐Term Energy Storage

“…Here, we therefore adopt the approach from Jorner et al. and approximate the biradical character using unrestricted open‐shell DFT . This approach yields Δ H ≠ values in good agreement with experiment and reference CASPT2 calculations for a series of diaryl‐substituted NBD compounds investigated earlier (Figure b) .…”

Evaluating Dihydroazulene/Vinylheptafulvene Photoswitches for Solar Energy Storage Applications

“…This device also works as ap roof-of-principle experiment toward future lab-to-site transfer.Sun light was focused on an apparatusconsisting of jacketed glass tubing (Figure 7). [17] In this case, asaturated solutionofDHA1 can give atheoretical limit storagee fficiency of 0.65 %i nt oluene.F or this experiment, a3 .7 10 À3 m toluene solution of DHA1 was pumped through the system at variable residence times, ranging from 35 st o4 17 s( ca. The DHA1 solution was pumped through the 5.8 mL outer jacket to maximize the direct exposure to sunlight.…”

“…Importantly, this heatingo ft he water can be exploited as an auxiliary product in hybrid water heating/MOST devices,a sw er ecently reported. [17] In this case, asaturated solutionofDHA1 can give atheoretical limit storagee fficiency of 0.65 %i nt oluene.F or this experiment, a3 .7 10 À3 m toluene solution of DHA1 was pumped through the system at variable residence times, ranging from 35 st o4 17 s( ca. 600 to 50 mL h À1 ), giving conversion percentages from 84 %u pto 100%.H owever,e stimation of the efficiency by using Equation (3) and assumingt hat the solarf lux was the standard AM1.5,t he measured maximum energys torage efficiencywas only 0.02 %, whichisf ar from the theoretical maximum of 0.45 %( Figure8).…”

“…Interestingly, an irradiation of 10 seconds resulted in about 80 % conversion in both cases. To put these numbers in context, solar energy conversion efficiencies have been reported under similar conditions for rutheniumf ulvalene (Ru 2 Fv) compounds( 0.0071%)m ainly limited by ap oor quantum yield and norbornadienes (up to 1.1 %), [2,17] limited by quantum yield and onset of absorption. To put these numbers in context, solar energy conversion efficiencies have been reported under similar conditions for rutheniumf ulvalene (Ru 2 Fv) compounds( 0.0071%)m ainly limited by ap oor quantum yield and norbornadienes (up to 1.1 %), [2,17] limited by quantum yield and onset of absorption.…”

“…The maximum measured energy storage efficiencyi nt he microfluidic chip was found to be 0.13 % at 4 10 À3 m and 0.034 %a t1 10 À3 m,a taresidence time of 3s,w hich are close to the theoretical limits (Figure 6c). To put these numbers in context, solar energy conversion efficiencies have been reported under similar conditions for rutheniumf ulvalene (Ru 2 Fv) compounds( 0.0071%)m ainly limited by ap oor quantum yield and norbornadienes (up to 1.1 %), [2,17] limited by quantum yield and onset of absorption.…”