Donor−Acceptor Thiolated Polyenic Chromophores Exhibiting Large Optical Nonlinearity and Excellent Photostability

Abstract

We have successfully utilized epoxyisophorone ring-opening chemistry to efficiently incorporate the butylthio group to the phenyltetraene bridge of highly efficient nonlinear optical chromophores in high overall yield. By following the guidance of Dewar’s rules, the sulfur atom functions as a moderate π-accepting group at a starred position of the conjugated bridge. Several of very critical material parameters of the phenyltetraenic chromophores for device applications have been intrinsically and simultaneously improved through such a simple and straightforward engineering of molecular structures. Compared with the nonsubstituted analogue 2, thiolated chromophore 1 achieves higher molecular hyperpolarizability (34%), enhanced E-O coefficient (38%), significantly improved photochemical stability against 1O2 (by an order of magnitude), and better optical transparency (17 nm blue-shifted λmax absorption spectrum).

Balancing High Open Circuit Voltage over 1.0 V and High Short Circuit Current in Benzodithiophene‐Based Polymer Solar Cells with Low Energy Loss: A Synergistic Effect of Fluorination and Alkylthiolation

“…As the three synthetic steps illustrated in Scheme 1, such a synthetic route avoided the synthetically unfavored trimethylsilyl (TMS) protection and deprotection procedure, appearing more sound when comparing to the synthesis of similar mono mer (fluorinated alkylthieonyl BDT) by Hou and co-workers [10] The resulted key monomer M1 (BDTT-SF) was fully characterized by 1 H NMR, 13 C NMR, and matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). To obtain the target polymer PBDTT-SF-TT and PBDTT-SF-BDD, the polymerization was carried out by a Pd(PPh 3 ) 4 (PDI) of 2.53 for PBDTT-SF-TT and M n of 33 400 Da with a PDI of 3.92 for PBDTTT-SF-BDD, respectively.…”

“…1 H NMR (600 MHz, CDCl 3 ): δ (ppm) 7.20 (dd, 1H), 6.79 (dd, 1H), 2.74 (m, 2H), 1.51-1.20 (m, 9H), 0.88 (t, 3H), 0.85 (t, 3H) ( Figure S9, Supporting Information). 13 Figure S10, Supporting Information).…”

“…1 Figure S11, Supporting Information). 13 C NMR and degassed three times by using nitrogen at −78 °C. After removing the dry-ice bath, the solution was heated to 110 °C and stirred for 40 h under nitrogen protection.…”

Theoretical Study of Effect of the Number of N,N-dimethyl-4-nitroaniline Units in Novel “Parallel Connection” Chromophores on Its Nonlinear Optical Properties

“…Chromophores always play a key role in design of effective NLO materials. The first hyperpolarizability β of a chromophore increases with increasing length of the conjugated π system and increasing strength of the donor and/or acceptor [9][10][11][12][13]. Generally, an increase in the β value is accompanied by a bathochromic shift due to a larger π-conjugated length and/or stronger donor and acceptor ability [9][10][11][12][13].…”

“…The first hyperpolarizability β of a chromophore increases with increasing length of the conjugated π system and increasing strength of the donor and/or acceptor [9][10][11][12][13]. Generally, an increase in the β value is accompanied by a bathochromic shift due to a larger π-conjugated length and/or stronger donor and acceptor ability [9][10][11][12][13]. Therefore, there is always a tradeoff between nonlinearity and transparency [14][15][16][17][18][19][20][21][22][23].…”