IonMonger v1.2

This version adds the ability to simulate energy band offsets between the TLs and metal contacts, by changing the outer boundary conditions on the majority carrier densities in the TLs. This change introduces the new (optional) parameters Ect and Ean, namely the cathode and anode workfunctions, which may now be varied independently.

Only one modification of the model is required and this is to switch the outer boundary conditions on the majority carrier density in each transport layer to:

• n = gcE * exp((Ect - EcE) / VT) at the cathode/ETL contact, and
• p = gvH * exp((EvH - Ean) / VT) at the HTL/anode contact.

where gcE is the effective conduction band DoS in the ETL, Ect is the workfunction of the cathode, EcE is the conduction band edge in the ETL, gvH is the effective valence band DoS in the HTL, EvH is the valence band edge in the HTL, Ean is the workfunction of the anode, and VT is the thermal voltage. So, the only new parameters are the metal workfunctions Ect and Ean which need to be specified in the parameters file, otherwise they are set to EfE and EfH, respectively, for backwards compatibility.

The built-in voltage is then set equal to the difference between the metal workfunctions Ect-Ean, rather than EfE-EfH.

This model can be expected to be valid provided that:

• the majority carrier densities in the TLs remain low enough that the use of Boltzmann statistics is valid (approximately, this requires n < gcE/20 and p < gvH/20, or a gap of more than 3kBT between the quasi-Fermi level and the band edge),
• the minority carrier densities in the TLs have a negligible effect on the potential, and
• there are negligible losses due to recombination occurring at the metal/TL interfaces.

This version also adds one new plotting script called plot_dstrbns.m.