Hot-carriers in organic photovoltaics

Photogenerated charge carriers in organic photovoltaics (OPVs) suffer relaxation and recombination losses. However, extracting these carriers at higher energy (‘Hot-carriers’) has been found to be effective to overcome such loss pathways and improve efficiency of OPVs. Excess energy and long delocalization length promotes hot-carrier escape from Coulombic attraction and dissociation into free charges. Here, I have reviewed the ways to generate hot-carriers and their extraction in organic backbones. In-depth understanding of their energetics and dynamics will help designing hot-carrier photovoltaics.

Combined effect of ether and siloxane substituents on imidazolium ionic liquids

The combined effect of ether and siloxane substituents on imidazolium cations helps overcome the Coulombic attraction, van der Waals forces, size factor and conformational degree of freedom, and exerts an impact on viscosity, density and thermal properties of ionic liquids.

Internal Cation Mobilities in the Molten Binary Systems KNO3-Sr(NO3)2 and KNO3-Ba(NO3)2

The relative differences in internal cation mobilities for the molten binary systems (K, Sr0.5)NO3 and (K, Ba0.5)NO3 have been measured with the Klemm method in the concentration range up to 34 mol% of the alkaline earth cations. From these and available data on the densities and conductivities, the internal mobilities of these cations, bK, bSr and bBa, have been calculated. In these systems bK and bSr or bBa decrease with decreasing concentration of the K+ ion. bK is well expressed by bK = fK ·bK*=fK·[A/(V-V0)] exp (-E/RT), where bK* is the internal mobility of the K+ ion in such melts as (K,Cs)NO3 in which the Coulombic attraction is the dominant factor for the internal mobility of the K+ ion, the constants A, V0, and E being independent of the coion, V is the molar volume of the present mixture and fK the volume fraction of KNO3 in the mixture. At a given mole fraction of K+ ions, the internal mobilities are in the order: Ca<Sr<Ba. This order could be interpreted as the decreasing order of the Coulombic attraction of these cations with the anion.

Low Temperature Interactions Between Gold and Iron in Silicon

ABSTRACTThe annealing kinetics of the gold-iron complex have been studied over the temperature range from room temperature to 400°C. From a consideration of the charge states of the gold and iron centres at room temperature it was concluded that the pairing was by Coulombic attraction. The binding energy of the centre was found to be 1.22 eV.During the annealing processes the interstitial iron was found to be precipitating and this was shown to modify the details of the growth and dissociation rates of the gold-iron complex.