TY - JOUR
T1 - Metal-Carbodithioate-Based 3D Semiconducting Metal-Organic Framework: Porous Optoelectronic Material for Energy Conversion
AU - Li, Xinlin
AU - Anderson, Ryther
AU - Fry, H.
AU - Pratik, Saied
AU - Xu, Wenqian
AU - Goswami, Subhadip
AU - Allen, Taylor
AU - Yu, Jierui
AU - Rajasree, Sreehari
AU - Cramer, Christopher
AU - Rumbles, Garry
AU - Gomez-Gualdron, Diego
AU - Deria, Pravas
PY - 2023
Y1 - 2023
N2 - Solar energy conversion requires the working compositions to generate photoinduced charges with high potential and the ability to deliver charges to the catalytic sites and/or external electrode. These two properties are typically at odds with each other and call for new molecular materials with sufficient conjugation to improve charge conductivity but not as much conjugation as to overly compromise the optical band gap. In this work, we developed a semiconducting metal-organic framework (MOF) prepared explicitly through metal-carbodithioate "(-CS2)nM" linkage chemistry, entailing augmented metal-linker electronic communication. The stronger ligand field and higher covalent character of metal-carbodithioate linkages-when combined with spirofluorene-derived organic struts and nickel(II) ion-based nodes-provided a stable, semiconducting 3D-porous MOF, Spiro-CS2Ni. This MOF lacks long-range ordering and is defined by a flexible structure with non-aggregated building units, as suggested by reverse Monte Carlo simulations of the pair distribution function obtained from total scattering experiments. The solvent-removed "closed pore" material recorded a Brunauer-Emmett-Teller area of ~400 m2/g, where the "open pore" form possesses 90 wt % solvent-accessible porosity. Electrochemical measurements suggest that Spiro-CS2Ni possesses a band gap of 1.57 eV (..sigma.. = 10-7 S/cm at -1.3 V bias potential), which can be further improved by manipulating the d-electron configuration through an axial coordination (ligand/substrate), the latter of which indicates usefulness as an electrocatalyst and/or a photoelectrocatalyst (upon substrate binding). Transient-absorption spectroscopy reveals a long-lived photo-generated charge-transfer state (tCR = 6.5 us) capable of chemical transformation under a biased voltage. Spiro-CS2Ni can endure a compelling range of pH (1-12 for weeks) and hours of electrochemical and photoelectrochemical conditions in the presence of water and organic acids. We believe this work provides crucial design principles for low-density, porous, light-energy-conversion materials.
AB - Solar energy conversion requires the working compositions to generate photoinduced charges with high potential and the ability to deliver charges to the catalytic sites and/or external electrode. These two properties are typically at odds with each other and call for new molecular materials with sufficient conjugation to improve charge conductivity but not as much conjugation as to overly compromise the optical band gap. In this work, we developed a semiconducting metal-organic framework (MOF) prepared explicitly through metal-carbodithioate "(-CS2)nM" linkage chemistry, entailing augmented metal-linker electronic communication. The stronger ligand field and higher covalent character of metal-carbodithioate linkages-when combined with spirofluorene-derived organic struts and nickel(II) ion-based nodes-provided a stable, semiconducting 3D-porous MOF, Spiro-CS2Ni. This MOF lacks long-range ordering and is defined by a flexible structure with non-aggregated building units, as suggested by reverse Monte Carlo simulations of the pair distribution function obtained from total scattering experiments. The solvent-removed "closed pore" material recorded a Brunauer-Emmett-Teller area of ~400 m2/g, where the "open pore" form possesses 90 wt % solvent-accessible porosity. Electrochemical measurements suggest that Spiro-CS2Ni possesses a band gap of 1.57 eV (..sigma.. = 10-7 S/cm at -1.3 V bias potential), which can be further improved by manipulating the d-electron configuration through an axial coordination (ligand/substrate), the latter of which indicates usefulness as an electrocatalyst and/or a photoelectrocatalyst (upon substrate binding). Transient-absorption spectroscopy reveals a long-lived photo-generated charge-transfer state (tCR = 6.5 us) capable of chemical transformation under a biased voltage. Spiro-CS2Ni can endure a compelling range of pH (1-12 for weeks) and hours of electrochemical and photoelectrochemical conditions in the presence of water and organic acids. We believe this work provides crucial design principles for low-density, porous, light-energy-conversion materials.
KW - light-harvesting
KW - metal-carbodithioate linkage
KW - metal-organic framework
KW - photoelectrocatalysis
KW - through-bond conductivity
UR - http://www.scopus.com/inward/record.url?scp=85162881114&partnerID=8YFLogxK
U2 - 10.1021/acsami.3c04200
DO - 10.1021/acsami.3c04200
M3 - Article
SN - 1944-8244
VL - 15
SP - 28228
EP - 28239
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 23
ER -