Bibtex- can't get my citations to work

Question

I am trying to create my citations and I am really frustrated. Whenever I try to compile my .bib with BibTeX I get this error

Process started

I couldn't open file name `sample.aux'

Process exited normally

When I try to cite something in my text with \cite{} I can see all my citations, but when I try to compile (pdflatex+bib(la)tex +pdflatex(x2)+ show pdf) I get this message:

Process started

This is BibTeX, Version 0.99d (MiKTeX 2.9.6630 64-bit)
The top-level auxiliary file: Project DLC.aux
The style file: biblatex.bst
White space in argument---line 6 of file Project DLC.aux:
\citation{Grigoriadis : diss} I'm skipping whatever remains of this command
Database file #1: Project_DLC-blx.bib
Database file #2: sample.bib
"{" immediately follows a field name---line 49 of file sample.bib :
year : {1978}, I'm skipping whatever remains of this entry
I was expecting a `,' or a `}'---line 53 of file sample.bib: 
@article{Grigoriadis : diss, I'm skipping whatever remains of this entry
I was expecting a `,' or a `}'---line 61 of file sample.bib: 
@article{Elmahdy : diss, I'm skipping whatever remains of this entry
Biblatex version: 3.8
(There were 4 error messages)

Process exited with error(s)

I am also using the following packages:

\usepackage[style=ieee,backend=bibtex,autolang=other]{biblatex}
\addbibresource{sample}
\usepackage{csquotes}

and \printbibliography at the end of the doc. I cant really understand what's going on so I could use some help! Also here is the part that i want to cite, if that helps:

Οι θερμοτροπικοί με την σειρά τους διακρίνονται σε δύο κατηγορίες: Τους ραβδόμορφους υγρούς κρυστάλλους (ΡΥΚ) και τους δισκόμορφους υγρούς κρυστάλλους (ΔΥΚ) (Εικόνα 1). Στην παρόυσα εργασία θα ασχοληθούμε αποκλειστικά με τους θερμοτροπικούς ΔΥΚ.\cite{Grigoriadis diss}

Here is my sample.bib

@ARTICLE{Feng2009421,
author={Feng, X. and Marcon, V. and Pisula, W. and Hansen, M.R. and Kirkpatrick, J. and Grozema, F. and Andrienko, D. and Kremer, K. and Müllen, K.},
title={Towards high charge-carrier mobilities by rational design of the shape and periphery of discotics},
journal={Nature Materials},
year={2009},
volume={8},
number={5},
pages={421-426},
hyphenation="english",
}

@ARTICLE{Grigoriadis20101403,
author={Grigoriadis, C. and Haase, N. and Butt, H.-J. and Müllen, K. and Floudas, C.},
title={Negative thermal expansion in discotic liquid crystals of nanographenes},
journal={Advanced Materials},
year={2010},
volume={22},
number={12},
pages={1403-1406},
hyphenation="english",
}

@ARTICLE{Laschat20074832,
author={Laschat, S. and Baro, A. and Steinke, N. and Giesselmann, F. and Hägele, C. and Scalia, G. and Judele, R. and Kapatsina, E. and Sauer, S. and Schreivogel, A. and Tosoni, M.},
title={Discotic liquid crystals: From tailor-made synthesis to plastic electronics},
journal={Angewandte Chemie - International Edition},
year={2007},
volume={46},
number={26},
pages={4832-4887},
hyphenation="english",
}

@ARTICLE{Sergeyev20071902,
author={Sergeyev, S. and Pisula, W. and Geerts, Y.H.},
title={Discotic liquid crystals: A new generation of organic semiconductors},
journal={Chemical Society Reviews},
year={2007},
volume={36},
number={12},
pages={1902-1929},
hyphenation="english",
}

@ARTICLE{C.N.R.RAO,
author={C.N.R.Rao and K.J.Rao},
title={Phase Transitions in Solids},
journal={McGraw-Hill, USA},
year{1978},
hyphenation="english",
}

@ARTICLE{Grigoriadis diss,
author={Grigoriadis, C.},
title={Doctoral dissertation - Graphene discotic liquid crystals: self-assembly and dynamics},
journal={University of Ioannina},
year{2014},
hyphenation="english",
}

@ARTICLE{Elmahdy diss,
author={Elmahdy, M.M.},
title={Doctoral dissertation - Self-assembly and Dynamics of Liquid Crystals},
journal={University of Ioannina},
year{2008},
hyphenation="english",
}

@ARTICLE{Sweicher,
author={Seweicher, G. and Olivier, Y. and Lemaur, V. and Geerts, Y.H.},
title={What Currently Limits Charge Carrier Mobility in Crystals
of Molecular Semiconductors?},
journal={Isr.J.Chem.},
year={2014},
volume={54},
pages={595-620},
hyphenation="english",
}


@ARTICLE{Takimiya20114347,
author={Takimiya, K. and Shinamura, S. and Osaka, I. and Miyazaki, E.},
title={Thienoacene-based organic semiconductors},
journal={Advanced Materials},
year={2011},
volume={23},
number={38},
pages={4347-4370},
hyphenation="english",
}