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 be used to construct product development and test facilities near Oxford and to attract new talent.

OPV is commercialising transparent, inexpensive, and nontoxic solar cells which can be printed onto glass in a range of colours; essentially an electricity-generating stained glass window. The technology was first developed at Oxford University’s Department of Physics by Dr Henry Snaith.

Kevin Arthur, CEO of OPV said “Our company is making huge strides in the scale-up and commercialisation of this technology, our new product development facility at Begbroke will incorporate state of the art printing techniques to enable us to manufacture larger modules and begin the technology transfer of our new, high efficiency MSSC technology.”