Novel polymeric metal complexes of pyridine derivatives for being used as dye sensitizers

Novel and high photovoltaic performance sensitizers of copolymeric sulfur coordination metal complexes of benzimidazolyl benzodithiophene derivatives

“…[21][22][23][24][25] Since the proposal of D-A 0 -p-A motif, the focus of researching sensitizers has changed from the donor D and the acceptor A to auxiliary acceptor A 0 , because of strong electron-absorbing ability, benzothiadiazole (BTD), 26,27 benzotriazole (BTZ), [28][29][30] benzopyrazine (PPZ), [31][32][33] and dipropylphthalata (DPP) [34][35][36] have also been extensively studied for being used as auxiliary electron acceptors. During the study of the auxiliary electron acceptor A 0 , it was found that these pure organic auxiliary electron acceptors limit the ability of the intramolecular charge transfer (ICT), electron-withdrawing ability as well as the push-pull electron balance, 37 and that the metal complexes were able to overcome these drawbacks by modulating the strength of the coordination bonds between the metal and the ligand. In recent years, metal complexes with N and O as coordinating atoms have been used as auxiliary electron acceptors, and their PCE has been increased to near 10%, but still not more than 10%, and it is also found that the stronger the coordination bond energy of the metals (Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II)) with the coordinating atoms N and O is, the higher the PCE is ref.…”

“…In recent years, metal complexes with N and O as coordinating atoms have been used as auxiliary electron acceptors, and their PCE has been increased to near 10%, but still not more than 10%, and it is also found that the stronger the coordination bond energy of the metals (Ni( ii ), Cu( ii ), Zn( ii ), Cd( ii ), and Hg( ii )) with the coordinating atoms N and O is, the higher the PCE is ref. 37–40. According to the soft and hard acid–base principle, 41,42 S atom is a softer base than O and N atoms, and the complexes of S coordinating with soft acids (Ni( ii ), Cu( ii ), Zn( ii ), Cd( ii ), and Hg( ii )) will have stronger coordination bonds than those with O and N, this will facilitate the enhancement of the electron-withdrawing ability of the auxiliary electron acceptors (A′) and improve the push–pull electron balance within the sensitizer molecule, thereby improving the absorption of spectral range and intensity of the sensitizer and enhance the photovoltaic performance.…”

Sensitizers of Metal Complexes with Sulfur Coordination Achieving a Power Conversion Efficiency of 12.89%

“…Organic dye sensitizers have many advantages, such as higher V oc , the availability of higher performance dyes in a wide range of colors, etc., but there are also some disadvantages, such as poor thermal stability, low molar extinction coefficients, and poor PCE enhancement. , However, adopting metal complexes to replace the above organic compounds as auxiliary electron acceptors can improve the thermal stability of dyes sensitizer, improve the molar extinction coefficient, enhance intramolecular charge transfer (ICT) ability, and strengthen their electron-withdrawing ability. , The electron-withdrawing ability of the auxiliary electron acceptor can be regulated by the strength of the coordination bond between the central metal and the ligand . The stronger the coordination bond, the greater the electron-withdrawing ability of the complex, which facilitates intramolecular electron transfer. − According to the soft and hard acid–base principle, the strength of the coordination bond is regulated by the ligand atom and metal ions. − For a series of soft acid metal ions Ni­(II), Cu­(II), Zn­(II), Cd­(II), and Hg­(II), the coordinating ability of soft base sulfur (S) with them is stronger than that with oxygen (O) and nitrogen (N), which can cause the coordinate bond of these metal with sulfur (S) to be stronger than that with oxygen (O) and nitrogen (N) and therefore will enhance the electron-withdrawing ability of auxiliary electron acceptor and improve their photovoltaic performance.…”