Cleantech firm Oxford Photovolatics Limited (OPV), an Oxford University spin-out, has received £2m ($3.01m) from existing investor MTI Partners.

Spun out by Oxford’s tech transfer unit Isis Innovation in 2011, OPV has gone on to raise a total of $4m in venture funding. MTI previously invested in the UK-based firm in 2011 as part of a £650k ($1m) round.

The funds raised in the latest round, which also saw investment from Oxford University and a number of private investors, will…